Beloved, eh? Aw, shucks.
Both Carrefour and Super U have cash points and will take pretty much any card with a Visa or MasterCard connection! The supermarkets themselves will also take plastic, no probs. These days they will ask you if you want to pay in euros or sterling with your card - opt for the latter if your card provider charges a fee for continental transactions. Pick euros if you have a Nationwide card as they give a much better rate than you'll be offered and charge no fee.
I've never stayed on BSJ so can't help you re the walk, but I'd say Super U. If you're arriving on foot from the station, you can also get cash out at the bank opposite the building site which is now the North entrance!!