NL50: Shortstack shoves against my AK reraise..?

[bigslicknuts]

Poker Stars - No Limit Hold'em Cash Game - $0.25/$0.50 Blinds - 9 Players - (LegoPoker Hand History Converter)

Hero (SB): $77.85
BB: $26.20
UTG: $55.15
UTG+1: $40.30
MP1: $29.25
MP2: $46.60
MP3: $21.85
CO: $47.25
BTN: $60.75

Preflop: Hero is dealt A[img]/images/graemlins/spade.gif[/img] K[img]/images/graemlins/club.gif[/img] (9 Players)
4 folds, <font color="red">MP3 raises to $1.50</font>, CO folds, BTN calls $1.50, <font color="red">Hero raises to $5.00</font>, BB folds, <font color="red">MP3 raises to $18.00</font>, BTN folds, <font color="red">Hero ?? </font>

Villain is 41.9/16.1 over only 26 hands at the table...
Whats you're line? What hands would you say his range includes?