50NL - trapping a player to call, what amount to raise?

[clowntable]

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

Reads
MP: limps any Ace, overvalues TP when his Ace hits
Button: Seems solid

BB ($18.65)
UTG ($73.75)
MP ($19)
Button ($69.20)
Hero ($57.55)

Preflop: Hero is SB with 7[img]/images/graemlins/spade.gif[/img], 7[img]/images/graemlins/club.gif[/img].
<font color="#666666">1 fold</font>, MP calls $0.50, <font color="#CC3333">Button raises to $2</font>, Hero calls $1.75, <font color="#666666">1 fold</font>, MP calls $1.50.

Flop: ($6.50) A[img]/images/graemlins/club.gif[/img], T[img]/images/graemlins/diamond.gif[/img], 7[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(3 players)</font>

The perfect flop for us. Gameplan is to check and let MP bet for us then CR after Button is in the pot, too.

Hero checks, <font color="#CC3333">MP bets $2.5</font>, <font color="#CC3333">Button raises to $7.5</font>, Hero calls $7.50, <font color="#CC3333">

Well that worked out great. Assuming that MP has his A he will push here

MP raises to $19.5 (All-In)</font>, Button calls $9.50,

Ok, all went according to plan. I put button on AQ, AK, AT, TT (and a longshot 98).

Hero ???

I think I push here but maybe I should raise a very small amount virtually forcing Button to call and push any turn. I guess it makes no difference though and I should just push to not let him get away if he has the rare 98 or some pair like KK/QQ/JJ and will only call if making a hand?