But the new iMacs are coming out next week!
Ditto the comment on the RAM. 4GB can be had for less than a hundred bucks. You'll be happy you have it if you find yourself using Parallels often.
Photos, documents and bookmarks are easy. Pictures can be dragged and dropped right into iPhoto if you plan on using it. Documents (assuming these to be MS Office) can just be copied to the Mac and will open natively in Office 2008 for the Mac. Not sure what browser you're using on the PC side, but nearly every browser has an option to export bookmarks, which can then be imported into the Mac counterparts.
The files can be transferred by connecting an Ethernet cable between the Mac and the PC and using file sharing, but you may just as well get an external hard disk (if you don't already own one) to help facilitate the transfer. After all, when you're done you can reformat the drive and use it with Time Machine to keep your data backed up.