Local DR Sim card data charges

I visited the DR with my family last year, and because I run my own business, it was necessary for me to use my UK Orange mobile to connect as a modem to get emails etc. I ended up with a bill over ?800 when I got back, which was nice. What I want to know is can I buy a PAYG Orange Dominica sim card that will just go into my own Orange handset, and use that to connect for data? If so, where do I get one from and does anyone know what the data charges are in the DR?

I'm afraid I don't have family in the DR - is it possible to get a short term contract? I just don't want to be landed with ?8 per MB charge again!! I'm unlikely to make many calls - it's purely data I have an issue with.