If you plan on using more than four gigs of ram then I would recommend upgrading to the 64bit version of windows. No, you can't just upgrade, however, you can save your user profile, pictures, settings, and everything else using the microsoft user state migration tool found here: (Its free)http://www.microsoft.com/downloads/en/details.aspx?FamilyID=1d9f14c2-670f-4576-9415-ec91f0f42ccc
Once you back up your data to and external drive using this tool, do a fresh install of microsoft windows 64bit. Install all your programs that you had from your old computer, then install the User State Migration Tool and select new computer to import all the settings. It sounds harder than it really is, but there is no need for the 32 bit windows anymore.