Hi,
You should book your car online before you go. It works out much cheaper. The beach at Julia's is the best in the area and has some gorgeous restaurants. For evening eating out I would recommend Caso do Campo, Florians, Fuzio's, Paixa and The Thai Garden. If you pick up The Central Algarve magazine you there is a map showing where all restaurants are and what is on in the region. You can pick the mag up in most of the restaurants, receptions and shops.
Enjoy!