Problems during installation - how to recover lost files?

I am new to the forums and not completely familiar with all of the terms I'm reading, so please excuse me if I'm not clear on the explanation of my problem or following expected protocol....

First the background - I was previously running Parallels 3.0 on my MacBook using Leopard and went to the Genius bar to resolve an email problem. Long story short - they did an upgrade to Snow Leopard and when they discovered after the fact that Parallels 3.0 won't run under Snow Leopard, gave me a new (not upgrade to) Parallels 5.0 along with an apology.

When I began installing the new Parallels 5.0, there was a message that Parallels 3.0 would be removed. I stopped the installation in order to do a data backup, but now can't find the data.

I now know that I should have done a backup about 24 hours ago before starting any of this, but it's too late to go back. Is there any way to access and restore my data? I am not familiar with the different files and how they are used, but I see a WinXp.hdd file that was created yesterday about the time the Snow Leopard upgrade was performed. Any help/suggestions would be greatly appreciated.