Cannot get cover open and damaged large too in the process

I tried to open the case on my iPod G3 to replace the battery. I could not get the case open and damaged the large tool in the process. (The sharp edge is completely ruined!) The small tool appears to be useful but is also showing signs of wear. Is there another tool that could be used or could I get a replacement. I know the instructions said it would be difficult, but it was more difficult than I expected.

Billy Blanchard

Thousand Oaks, Ca.