Villain is unknown but definitely not a reg. Has done a little bit of open limping

If we were to raise, would we raise turn or river? Or is it better to just call down here?

Full Tilt No-Limit Hold'em, $0.50 BB (8 handed) - Full Tilt Converter Tool from FlopTurnRiver.com

saw flop

UTG+1 ($63.35)
MP1 ($43.90)
MP2 ($52.90)
Hero (CO) ($102.20)
Button ($50)
SB ($52.25)
BB ($82)
UTG ($60.20)

Preflop: Hero is CO with J, K
2 folds, MP1 calls $0.50, 1 fold, Hero bets $2.25, 2 folds, BB calls $1.75, MP1 calls $1.75

Flop: ($7) K, 9, 5 (3 players)
BB checks, MP1 bets $3.50, Hero calls $3.50, 1 fold

Turn: ($14) 2 (2 players)
MP1 bets $4, Hero calls $4

River: ($22) 5 (2 players)
MP1 bets $4, Hero calls $4

Total pot: $30 | Rake: $1.50