Hello, I pasted this information from the Travel section of the New York Times Online. I would suggest checking out the websites and/or making phone calls to verify how current this info is!
In Old San Juan, free trolleys can take you around, and the tourist board can provide you with a copy of Qué Pasa, which contains a self-guided walking tour. The Caribbean Carriage Company (PHONE: 787/797-8063) gives Old City tours in horse-drawn carriages. Look for these buggies at Plaza Dársenas near Pier 1; the cost is $30 to $60 per couple. Cordero Caribbean Tours (PHONE: 787/786-9114; 787/780-2442 evenings). Normandie Tours, Inc. (PHONE: 787/722-6308). Rico Suntours (PHONE: 787/722-2080 or 787/722-6090, www.ricosuntours.com). Tropix Wellness Outings ( PHONE: 787/268-2173). United Tour Guides (PHONE: 787/725-7605 or 787/723-5578, www.unitedtourguides.com). Wheelchair Getaway (PHONE: 787/883-0131).
Voyager of the Seas: October 2004
Adventure of the Seas: December 2006
You can contact the Caribbean Carriage Corporation at 787-397-1747 or 787-360-5686 they are a very nice, local family owned Carriage Ride Company in Old San Juan Puerto Rico! I believe those are the updated numbers (as of Dec 2014 at least). I know you guys don't need them any more, but maybe someone else can benefit at this point. I had a hard time finding them online, so I just asked when I was there! hope this helps!