If you are still trying to sort out your transportation, I would recommend looking into Celebrity Limo. I just booked them for mini-buses, limos & Rolls Royce for my September wedding. They were so helpful and patient with my million questions and I have high hopes their service on the day of will be the same.
Also, the main selling point for me was that they offer one-way transfers (pay for pick up @ Point A, drop off @ Point B only, as opposed to 3 or 4-hour minimums). I had a very difficult time finding limo companies that did not require a minimum number of hours. I am having a second line from the Cathedral to my reception and only need pick up from the hotel to the church and that's it. Celebrity's ability to charge for just what I need cut the transportation cost literally in half.
Just wanted to give them a recommendation while it was on my mind!