Opp. is 51/11/3.75 after ~70 hands. Raise/call?

Party Poker No-Limit Hold'em, $ BB (10 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

MP3 ($35.70)
CO ($20.95)
Hero ($93.25)
SB ($168.11)
BB ($20.27)
UTG ($105.80)
UTG+1 ($80.30)
UTG+2 ($60.85)
MP1 ($56.15)
MP2 ($66.80)

Preflop: Hero is Button with K, Q. SB posts a blind of $0.50.
UTG calls $1, 3 folds, MP2 calls $1, 2 folds, Hero calls $1, SB (poster) completes, BB checks.

Flop: ($5) 6, 8, Q (5 players)
SB checks, BB checks, UTG checks, MP2 checks, Hero bets $3, SB folds, BB folds, UTG calls $3, MP2 folds.

Turn: ($11) Q (2 players)
UTG checks, Hero bets $8, UTG calls $8.

River: ($27) 3 (2 players)
UTG bets $15, Hero..