Wow, I'm on a roll today. I was just reading about complete glass replacements on WWM and ran across your problem. I have never owned an acrylic tank, so I have not researched it (and really can not offer much advice) but to look here.
http://www.wetwebmedia.com/acrylictkrepfaqs.htm It is a bunch of questions that have been asked about how to fix problems on acrylic tanks. If your question is not answered, there is another page of FAQ's on the same site.
Good luck