Garcia hit her homer over the left-field wall in the top of the first, driving home sophomore right fielder Katie Hnatyk and sophomore catcher Joey Daniels.
Iowa (39-19 overall, 12-7 Big Ten) made it 3-1 with a run in the bottom of the second but Garcia added her 18th RBI of the season in the top of the sixth, bringing home Daniels.
Badger junior pitcher Eden Brock (18-13) ended her season by striking out six batters, walking two and giving up just one run on eight hits in seven innings.
Iowa's Brittany Weil (27-13) gave up four runs on five hits while striking out five in seven innings.
The Badgers conclude their season with a 22-22 overall record (6-11 Big Ten), the first of head coach Chandelle Schulte's UW tenure. Iowa, meanwhile, advances to the Big Ten Tournament next weekend, which will be hosted by conference champion Northwestern.