There are many ATMs in Carvoeiro. Only use the ones attached to the banks, or the one inside Intermarche supermarket as all the others charge to exchange money. Do not accept the bank’s conversion as it will always cost more than your bank’s conversion. Eg recently they were charging £100 or more for 100 euros.
Credit Agricole is just along from Hemingways on the road out.
Millennium Bank is on the in road, in quite far up, on the RHS if you are walking up from the beach.