I didn't read where he said anything was wrong with what he had . . . just that he was looking for a new battery?
I have been using 6 volt batteries from Batteries Plus in my 32 Cabriolet for the last 8 years or so - have worked really well and are very affordable (about $105 with a core). What I don't know is the size/shape of your battery - so the ones from BP may or may not be what you need . . . but I'd check them out.
If you don't drive the car all the time, then buy a low-amp battery tender . . . they keep the battery charged while you're not using the car. I always disconnect my battery cables from the car when in long-term storage (like the Winter months).