Interesting AA hand - decisions on all streets

[aplunk]

$100 on-line tourney - 500 runners

starting stack is 2500 - 2nd level - blinds 15/30

i've raised a few times pre-flop, hoping to pick up pots one way or anther. it's not been going well - i'm down to 1900.

i'm multi-tabling so not paying enough attention, i haven't noticed villain, but he's got 3000 now.

hero is utg with A [img]/images/graemlins/club.gif[/img] A [img]/images/graemlins/spade.gif[/img]

hero raises to 90
MP1 calls
others fold

flop 10 [img]/images/graemlins/spade.gif[/img]5 [img]/images/graemlins/spade.gif[/img]4 [img]/images/graemlins/spade.gif[/img]
pot is 225

hero bets 100
MP1 calls

turn 4 [img]/images/graemlins/diamond.gif[/img]
pot is 425

hero checks
MP1 checks

river K [img]/images/graemlins/heart.gif[/img]
pot is 425

hero bets 300
MP1 raises to 600

hero ??

i have 1410
he has 2510
pot is 1325 and it's 300 to call

comments on all streets please, and details of how paying attention can improve your game