Mathematically correct, or not

[Duece Three]

Down to heads-up in a 1 table tourney.

I have roughly T3600, leaving villain w/T3400

I have A[img]/images/graemlins/heart.gif[/img] , 8[img]/images/graemlins/heart.gif[/img]
Villain has J[img]/images/graemlins/spade.gif[/img] , J[img]/images/graemlins/diamond.gif[/img]

For arguments sake, lets say that I knew his hand.

I'll win the hand roughly 30% of the time, and cash for $100.
I'll lose that hand roughly 70% of the time, and cash for $60.

How do I figure out if the long term results are positive, or am I completely misinterpreting something that I read (somewhere)?