I am with olbob... You can get a top and have it installed for about $700. I think they person that owned my car before me installed it on their own, and you can tell. It isn't as tight as it should be in spots.
If you do this, you should make sure you are very anal about everything. There is a reason that companies specialize in convertible tops only.
Remember, you do it wrong, it will blow off and you will be paying a pro even more to fix that.