Crashed App store App

I hope that someone a lot more tech savvy than I am can help. I purchased Wallet app from the Apple app store four years ago. When I launched it about 5 days ago, I got an error message saying that the app was "Damaged" and I should delete it from my HDD and re-download, which I did. But I then got another message saying that my OS (Snow Leopard) was out of date and that I had to upgrade to OSX Lion.

Apple support were helpful at first but after talking to three different people, the last person said "download Lion and that will fix it". Ok, so I bought Lion from the App store and upgraded.But when I launched Wallet it was empty: so I used my Time Machine backup to restore from a previous date and that loaded a second Wallet icon into my computer labelled Wallet Original but when I launched it, it also was empty of any of my data.

I tried to use the Import feature of Wallet but that didn't work either.

I understand that the problem is due to out of date security certificates but I also read that that issue had been fixed. So at the moment, all of my passwords and other info are lost. If anyone can provide a fix that will be great.

Thanks in advance.