First things first; in case you haven't already, go on-line and read John Palmer's "How to Brew" - great stuff there, it's where I started.
Second; if you're gonna do what you've suggested in your post, you'll get little to no conversion meaning there will be little to no fermentable sugars in the wort.
Here's what I'd do: (NOTE - Temperatures stated below are ESTIMATIONS ONLY - there are several variables to consider here, but this should get you real close. Also note; I am making the assumption you already know some basics of brewing, so bear with me if I come across elementary in some areas and more advanced in others)
A quick note about volumes: 11 Lbs of grain will absorb roughly 1.3 gallons of your mash water - if you started with 6 gallons, you should be left with roughly 4.7 gallons once the bag has drained. You should sparge with enough water to bring that volume back up to around 6.5 gallons meaning you'll need somewhere between 8-10 quarts of sparge water. More details on this below...
Assuming you want a 5.25 G batch, and also assuming you are doing this on a regular stove-top; in your 8-gallon pot, bring 6 gallons of water to 163 F and slowly lower the bag of crushed grains into the pot. Take water out as needed if 6 gallons proves to be too much, but start with 6 (my 8-G pot actually will hold 8.6 gallons before creating a disaster). This larger thermal mass will make it easier to maintain the mash temperature. It's OK if it makes the water go all the way to the top of the kettle. This much water at 163 F should stabilize at around 154 F once the water has absorbed into the grain, also assuming the grain is around 70 F or so. It may take several minutes for the grain to become fully saturated - move it around if you can to promote saturation.
After the grain has become fully saturated, check the temperature and maintain the mash at 154 F for 60 minutes. If your actual temperature is plus or minus a degree or so from 154 F, it is not such a big deal at this point. You can keep the lid on the pot for this step, it'll help keep the heat in. With this much thermal mass, the temperature should not drop that much in 60 minutes - you may not need to add any heat.
WARNING - Adding heat from a burner to maintain your desired temperature is tricky - add it slowly, do not use the HIGH setting - MEDIUM at the most, turn on only for a short time and turn back off, move the liquid around in the pot while heating, and check the temperature in several places while moving the liquid around - there will be hot spots and moving the liquid around will promote even heat distribution. TOO MUCH HEAT CAN DENATURE THE ENZYMES - DENATURED ENZYMES = LESS FERMENTABLE SUGARS.
Start heating a second smaller pot of sparge water - 8-10 quarts will do - to rinse (sparge) the grains after mashing. You'll want this water to be around 170 F.
Once 60 minutes has elapsed, remove the grain bag and hold the bag over the pot to drain (this isn't easy - it's going to be heavy). When I did Partial-Mash my bags held roughly 7 Lbs of grain, and I used a large strainer that I could rest on top of my pot and set the bag in it to let it drain. This was very handy! Once the bag has drained almost completely, start pouring the sparge water over the grain bag (I used a 2-cup measuring cup) - the idea here is to get that sparge water into the grain to rinse the sugars off the grain and into your pot. This will also bring your liquid level up, which is OK. You want to end up with around 6.5 gallons for the boil.
If this proves to be too much of a challenge, you can drop the grain bag into another pot with the 8-10 quarts of 170 F water in it, swish it around for a bit, pull it out and let it drain into that pot, and just dump the contents of that pot into your boil pot. Some folks don't even rinse the grain in the bag - they just pull, drain, and toss - your call.
After sparging is done, you now have a pot with around 6.5 gallons of dark sweet wort. Start the heat and bring it to a boil. Once boiling, add the hops and start a 60-minute timer. This is your queue to have a cold one - pour yourself a homebrew if you have it. If not, crack open one of your favorites and keep an eye on the boil - you don't want it to boil over, but you DO want a fairly vigorous rolling boil - DO NOT PUT THE LID ON DURING THE BOIL.
After the 60-minute boil, chill the brew as quickly as you can, remember to practice good sanitation, transfer to your fermentation vessel and pitch the yeast - aerate as best you can, put in a stopper and let it rip!
This was the short version, of course, and there is quite a bit more to it, but this should get you close to what you're looking for right now. You may want to consider getting a larger pot, but for now; start with the book How to Brew and go from there.
