Branden Frazier added 16 points for the Rams, who snapped a 10-game losing streak and won at St. Bonaventure for the first time since Jan. 28, 2009.
Fordham (7-24, 3-13 Atlantic 10) trailed 41-35 at the break but opened the second half on a 20-5 run to go up 55-46 with 12:35 left. St. Bonaventure responded with a 17-4 run to jump back on top, 63-59, with 6:48 showing.
Jermaine Myers hit a 3-pointer on the Fordham's next possession, sparking 12 straight points for the Rams. Gaston scored seven during the spurt as Fordham led from there.
The Bonnies (14-15, 7-9) shot 46 percent (23 of 50) but hit 9 of 27 3-pointers.