You may be better off asking that on eBay or in the CS3 and earlier forum.
I've never used eBay I admit, but as a student without current employment, I don't have a credit card, so cannot really buy anything online, unless I can send a postal order or similar. I can't buy anything from Amazon for this reason. It is a pity one can't post one message and link it to all forums, I've had to put up multiple posts.
Premiere Pro will not even open output from older versions (i.e. CS3 will not open CS2 output).
Did you try to open your CS2 Project in CS3? The reason that I ask is that most Projects from earlier versions will Import into later versions. About the only reason that one would likely have any problems doing so is if 3rd party hardware, like Matorx, or 3rd party Effects (that were not present in the later version), like Magic Bullet Looks were not present. Even then (Matrox Projects probably an exception), the Project should Import.
I've Opened (not Imported) Pr6.5 Mac Projects in PrPro 2.0 with only the loss of a 3rd party Transition, or two. I've converted PC PrPro 2.0 Projects to CS3 Mac Projects, so users could Open them in CS4 on their Mac's. I've even found that some Encore CS3 NCOR files will Open in Encore 2.0.
If you can not Open the Project, you should be able to Import it into the later version of the program. Now, going the other way, say CS4 to CS3 will probably never work (exception might be the Encore files from CS3 opening in Encore 2.0).