Which President Mark? There are two places called President on Soi 11 ...Grand President and President Solitaire I think...Nana BTS stop so 3 stops to Siam Square. Is there another President nearer Siam Square too?
A friend of mine often stays at the Asia Hotel and likes it. It's actually got a direct skytrain exit (Rajthevee stop) and is one stop from Siam Square so is very handy for shopping too. It's cheaper to book this kind of hotel on the internet....check a few online booking sites for the best deal. I've found Sawadee to be very efficient but there are others. Here's a link anyway so you can get an idea of the prices. There are travel reviews on that site too which might be useful when choosing a place.
http://www.sawadee.com/hotel/bangkok/asiabkk/
Like Mark I wouldn't stay too long in BKK....especially at the beginning of your holiday. Save the BKK shopping till the end so you don't have to carry it around with you on the rest of your trip. Stay a night or two to get over the jet lag if you like. Two hours traditional Thai massage is a good cure for that. You could also get a connecting flight straight to CM and save BKK for the end.