do you have any software? Got get a copy of beersmith, you can use it as a trial and it will help you calculate all these things you need. There are also some online calcs that will help you figure out how much water, the temps etc.
A couple of things you will want to do, preheat your MLT. If you need to hit 153 and the software says use 163.5 degree water, add 175.00 water to your MLT and let it sit for a bit to preheat the cooler. This will keep your heat loss to a minimum.
From throwing the numbers in beer smith it tells me
first strike is 3.5 gallons at 164.5 lets rest for 90 minutes at 153
I would then take your first runnings after 90 minutes and then sparge with 2 equals volumes to get your remianing volume needed, probably around 2.25 to 2.5 gallons each to reach 6.5 gallons (your milage will vary based on MLT deadspace and grain absorption). You can read more about batch sparge techniques at
http://www.suebob.com/brew/allgrain.htm. that is a very helpful guide for the first time All Grainer.
Other than that, keep your temps steady by preheating and make sure that grain has a nice crush and you should be fine.