Hi Stephen. My advice would be to take US$ - the exchange rate from sterling is still pretty good at the mo, they are easy to get, easy to spend in DR, you probably won't get pesos here in England anyway.
How much you will need for your trips really depends on where/who you book through. If you book via your rep you will pay top price because you are paying for the rep's commission. If memory serves me right you are staying at the Iberostar - either go to the mall at Playa Dorada just up the road and book there, or book with the guys on the beach. They are cheaper. Don't listen when the rep tells you it is not safe, or they are not insured, or the trips are different - they are all lies which the rep will use to try and protect her commission!
Can't help with the golfing costs I'm afraid, I don't play - hitting a little ball round a field is such a waste of Brugal time
