KK, A comes on the turn. What do I do?

[wyrd]

This is from a hand I just played. In the previous hand I had pocket Kings (yes, that's right, pocket Kings two hands in a row) and won quite a large chunk off hitting quad Kings. I just sat down at the table so I have no reads yet.

In any case, I'm unsure of what to do in the following situation. Any advice would be appreciated.

Ultimate Bet 0.25/0.50 Hold'em (9 handed) http://216.119.70.224/converter/hhconverter.pl

Preflop: Hero is MP3 with K[img]/images/graemlins/club.gif[/img], K[img]/images/graemlins/diamond.gif[/img].
UTG calls, <font color="#666666">3 folds</font>, <font color="#CC3333">Hero raises</font>, CO calls, <font color="#666666">3 folds</font>, UTG calls.

Flop: (7.40 SB) 3[img]/images/graemlins/spade.gif[/img], 6[img]/images/graemlins/heart.gif[/img], 4[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
UTG checks, <font color="#CC3333">Hero bets</font>, CO calls, UTG calls.

Turn: (5.20 BB) A[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(3 players)</font>
<font color="#CC3333">UTG bets</font>, Hero ?? What do I do?