You may as well replace the boot, you can pick a good one up from a vw scrappie dirt cheap.
It also would be worth you while to treat the rust properly and go for a paint job. As '87_project' said, for the price of a body kit and getting it fitted you may just as well getting the car respayed. If the rest of the body work is good you won't end up spending that much money on a simple blow over.