Fold Or Raise In This Spot?

[luckbalks]

Villain that went all in was 39/1/.5 . Is raising a good option here to isolate the all in player? If so how much?

Full Tilt Poker - No Limit Hold'em Cash Game - $0.50/$1 Blinds - 6 Players - (LegoPoker Hand History Converter)

SB: $97.00
BB: $183.35
UTG: $155.20
MP: $100.00
CO: $26.50
Hero (BTN): $110.20

Preflop: Hero is dealt 5[img]/images/graemlins/heart.gif[/img] 6[img]/images/graemlins/heart.gif[/img] (6 Players)
2 folds, CO calls $1.00, Hero calls $1.00, SB calls $0.50, <font color="red">BB raises to $5.00</font>, CO calls $4.00, Hero calls $4.00, SB calls $4.00

Flop: ($20) J[img]/images/graemlins/heart.gif[/img] 5[img]/images/graemlins/diamond.gif[/img] Q[img]/images/graemlins/heart.gif[/img] (4 Players)
SB checks, BB checks, <font color="red">CO bets all-in for $21.50</font>, <font color="red">Hero ?</font>