Id like to get a new bike, either a trek 7.2 or a giant Escape. Trouble is I don't really have the funds for it right now. I'm currently riding a Raleigh comfort/hybrid for my daily commute. The bike is a little small and has 26x1.95 tires on it. could it be more cost effective to change over to a 700x32 tire set up with new rims and a taller seatpost, to kind of fine tune the bike to my needs. Or just save the cash and pull the trigger on a new bike? I know I could try to find a used bike to better suit my needs but if I'm going to buy a bike, I want the next one to be new.

If I did try to change out the rims and tires, what kind of coin would that cost? I wouldn't be looking for anything fancy, just something a narrower.