Welcome to the site thedrunk
First we need to know if you are wanting to upgrade your motherboard or keep the one you have - If you are wanting to keep the one you have it would be easier for us if we knew exactly what it is you have - If you could look for model numbers on your motherboard - This would help us
It does appear you are using a 800 FSB processor and Gateway says you have support for a 1066 FSB processor - Its really up to how much you are willing to spend
What exactly is it you want us to help with - You are really asking questions that are going to have answers of different opinions - If you could be more specific that would help