Hey mate, i know how you feel, its so much easier with backups.
Their is a choice of using a Memory Card exploit, i did on my "Fat" Ps2, and it worked great. Also, the tool needed you can fabricate out of a old credit card in 10 minutes.
Heres a link if you want to take a look:
http://forums.afterdawn.com/thread_view.cfm/447517
Ive tried it and its worked wonders, hard maybe first time but worked perfectly.
Just give it some patience