Orange has the online recharge.
Under "Atencion En Linea" you enter your phone number and 4-digit access code. Inside the system you register your credit card and can recharge your prepaid Orange card via the web.
Validity:
RD$ 50 - 7 days
RD$ 100 - 21 days
RD$ 150 - 21 days
RD$ 200 - 50 days
RD$ 250 - 50 days
RD$ 300 to RD$ 500 - 60 days
RD$ 1000 and RD$ 15000 - 75 days
The credit card, once registered, has to go through verification process. International cards may have problems with this. I suggest you get Banco Leon prepaid VISA for RD$ 50 and load it up with money you will use to recharge your Orange card.
And you can also use the prepaid Leon VISA for ebay, Paypal, ATM's, online and retail purchases worldwide.