as the guys say mate,could be time for a new car !! once they rust you may cover it up a bit but that kinda problem allways returns,,,,your next car will probably rust eventually as well unfortunately cos thats what cars do a lot is rust - try and be a bit more picky next time you look around but in truth it is very hard to find a good un - or you could of course patch it up a bit and carry on,many do as the saying goes,,better the devil you know- good luck mate