If you format and partition after you've installed your rom, then you should lose all the info on your sd card. Anyway....
1. Check that you've downloaded the A2SD+ rom. Version 2.3 was released today, so maybe download that one.
2. Backup if you want to, using Titanium backup (I haven't actually done a restore, so not familiar with this), and/or creat an app list on app brain that you can resync your apps automatically after the install.
3. Do the partitioning and the formatting again. If you want to keep the contents of your sd card, just copy everything to your pc, and then at then end copy everything back. You're basically taking your FAT32 and creating a FAT32 and EXT partition.
4. Flash the rom, from Rom manager, and then the radio. Get these files from Leedroid's dropbox link. When you reboot, you should have a lot more internal memory - but also you don't have any apps installed besides what came with the rom. You may wish to use an app called Quick System Info PRO, it'll show you APPS2SD, Internal, System, and SD Card storage.
5. Reinstall all your apps using AppBrain - sync (lots of data). Your internal memory will still be used to some extent, but you will see A2SD storage start being used, and some Internal Storage.
OPTIONAL
6. Flash blue carbon theme - awesome! The same way you flashed the rom.
7. Brut maps - you might want to uninstall the stock maps - up to you.
I have 126 (user) apps/games, using A2SD 457MB Free:84.38, Internal 148 MB Free:23.75