Well if you do buy another ps2 don't use it for parts, just use it as your new ps2, and sell your broken one on ebay. You should get around 20 or so for it, so that will cut down on the cost of an new one a little bit.
Or go to ebgames/funcoland they might trade your old PS2 plus like maybe 80.00 or so (I really don't know) for an used/working one.
I really don't know anything on ps2 lasers so that would be my best bet.
Christmas is coming around the corner
--spid3r