Whatever you decide to do, once the new battery is fitted, get yourself a CTEK battery conditioner and leave it connected all the time the car is standing idle (especially for long periods), a constant low drain on the battery will kill it very quickly unless you keep the charge up by some external means
I used to kill a battery every winter whilst the car was laid up. Bought a CTEK about 10 years ago and the same battery lasted until last year when I put the car into storage over winter and forgot to give the storage place my CTEK. It came out of storage and the battery was goosed. By that time, Ford had stopped making the flat terminal batteries so had to get a replacement elsewhere