Figures from the announcement of a 5th season:
Since launching its fourth season on TBS Jan. 8, Cougar Town has averaged 2.8 million viewers, 1.7 million adults 18-49 and 812,000 adults 18-34 in Live + 7 delivery. The show ranks as TBS’s top original primetime series ever with adults 18-49 and total viewers. As part of Cougar Town‘s successful transition to cable, new episodes on TBS are drawing an audience whose median age is seven years younger than the show’s last season on broadcast.
Source:
http://tvbythenumbers.zap2it.com/2013/03/25/cougar-town-renewed-for-fifth-season-by-tbs/174927/ So sounds fairly promising. Small figures compared to other networks but decent for TBS it seems.