Hooked Jumper cables backward

Don't worry I've done this too. Couldn't see the symbols on the battery. When I did it though I was able to start it and keep it running (on a mitsubishi 3000gt) The only problem with it was I fried my altenator regulator so my voltage gauge was jumping like crazy. Does the battery have a charge to it? Check all your wires too, see if any of your ground wires are melted or bubbled at all as well as the wires to your starter. You can always take the starter out and take it to a parts store and have them test it to see if it is still working but I'd start with all the wires first.