We called the number for the church and spoke with Mercedes Garcia, the priest's sister. She told us that you do not have to go through the resort to get married at the church. As long as you give the priest all the documents necessary to get married in the church (the docs the Catholic church requires that you have to get married) and submit them to the priest atleast two months ahead of time, they can book the wedding. A donation is required, but the amount is something you work out with the priest before the wedding. Weekend weddings have to be scheduled around regular mass services that are held on Saturday and Sunday at 5:00.
The only time it is necessary to go through the resort is if you want rooms there or you want the resort to host the reception. If anyone is interested, to go through the resort, it is a mimimum of 15 rooms for 3 nights (approx. $9,000 b/c the rooms are an average of $200 per night) and the weddings fee is anywhere from $850 to $1,700. The reception cost is priced per person and is on average about $60 per person, as long as there are at least 25 people. If less, then the resort charges a $500 additional fee and more per person. (This is the price list for the resort good through Dec 2005, so it may be higher now.)
Hopefully this will be helpful for anyone who would like to get married at the church and cannot/doesn't want to go through the resort. One final note, I believe the phone number given is for the priest's home. We talked to several family members before talking to Mercedes. If you would like to call, I'd advise having someone who speaks fluent Spanish make the call.