50NL - A8o c/r in 3-bet pot gets raised

[Willem]

Villain has been fairly active the last rounds and has stats of something like 25/20/4 over a small sample.

PokerStars No-Limit Hold'em, $0.50 BB (5 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

UTG ($50.95)
MP ($67.70)
Button ($59.05)
Hero ($108.45)
BB ($46.05)

Preflop: Hero is SB with A[img]/images/graemlins/spade.gif[/img], 8[img]/images/graemlins/club.gif[/img].
<font color="#666666">2 folds</font>, <font color="#CC3333">Button raises to $2</font>, <font color="#CC3333">Hero raises to $6.5</font>, <font color="#666666">1 fold</font>, Button calls $4.50.

Flop: ($13.50) J[img]/images/graemlins/club.gif[/img], 4[img]/images/graemlins/diamond.gif[/img], 8[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">Button bets $9</font>, <font color="#CC3333">Hero raises to $23</font>, <font color="#CC3333">Button raises to $52.55</font>, Hero ...?

What do we do here? Do we have to call? Can we fold?