Some comments above about whether this was a keylogging hack. As someone else has said, that isn't the case. From what I've read and pieced together, this was a data intercept as the data enters some kind of payment system. It seems most likely that this hack intercepted the data right at the payment system, after any encryption of the transmission had been removed.
So, whether you used a stored credit card or typed the details in, makes no difference. Whatever data the payment system needs (BA have said, so far, that it's your name, address, email address, credit card number, expiry date and CVV number) would have been captured. The important thing to note is that only data sent during the timescale mentioned is impacted. For example, say you had three credit cards stored in the BA system and used one of them to buy a ticket on 15th August, and one on 25th. Only the card used on 25th August is impacted.
As any fraud will be reimbursed, if it were me and I needed a potentially-impacted credit card to survive my trip/holiday I'd just keep using it and deal with replacing it once I got home. Of course, if fraud is attempted while you're away and your credit card company catches it and blocks your card, THEN start worrying about how to fund the rest of your trip. Friends/family can wire money using Western Union, or use another card, or ask your bank what your options are. In those cases, keep all receipts (cost of phone calls, wire transfers etc etc) and submit a claim from BA once back.