Problems with iPhoto upgrader on iPhoto 7.1.5. HELP!

I installed and ran the iPhoto upgrader for iPhoto 7 in preparation to install a newer version of iPhoto (9 or later) so that i can get photo album and books printed via iPhoto. I downloaded a number of available iPhoto 9 upgrades, but none worked even through i had run the upgrader. I am now stuck with a MacBook (OS X 10.7.5) with a version of iPhoto that won't open (error message: You have made changes to your photo library using a newer version of iPhoto. Please quit and use the latest version of iPhoto) and also wo';t allow me to install any iPhoto upgrades. Help! I have tried to restore iPhoto from time machine, but that hasn't worked, plus trying the original install disk for my laptop hasn't worked, presumably because i have upgraded the OS a few times since i got it (it's a late 2008 dinosaur of a macbook!). I am worried that now i have lost my photos and will have to pay 50 quid for a iLife disk with no guarantee that it will work. All i really want to do is un-install the upgrader and return iPhoto to it's original 7.1.5 state. Is that possible? Also how can i check that my photos are still stored somewhere without being able to open iPhoto? Please help! Thank you.