Top 2 pair on draw heavy board ($50nl)

[myke11]

Poker Stars - No Limit Hold'em Cash Game - $0.25/$0.50 Blinds - 6 Players - (LegoPoker HH Converter)

SB: $50.20
Hero (BB): $50.00
UTG: $49.15
MP: $51.55
CO: $44.25
BTN: $50.75

Preflop: Hero is dealt K[img]/images/graemlins/heart.gif[/img] Q[img]/images/graemlins/club.gif[/img] (6 Players)
UTG calls $0.50, MP calls $0.50, CO calls $0.50, BTN folds, SB calls $0.25, Hero checks

Flop: ($2.50) J[img]/images/graemlins/spade.gif[/img] Q[img]/images/graemlins/heart.gif[/img] K[img]/images/graemlins/spade.gif[/img] (5 Players)
SB checks, <font color="red">Hero bets $2.50</font>, UTG folds, <font color="red">MP raises to $8.00</font>, 2 folds
Hero...?

Villian is 21/17/4 over 250hands (i have him as a 2buyin winner over that time period). Im not sure how to play this flop... I tend to lead towards a 3bet, perhaps to $16, but i dont know if thats bad.
Who just calls and why?

If you just call what do you do on a safe turn? Are you trying to get the $$ in or lose the minimum?

If you 3bet, do you have to call if he 4 shoves getting 3-1?