Hi, as this is more a networking problem, I've put it in the networking forum.
As for your answer, the cheapest (and best) answer if it is practical is just to run a long Ethernet cable from the router to the PS2.
Possibly a more practical, but more expensive option is to buy two Powerline ethernet adapters, connect one to the PS2 and the other to the router.
Something like
http://www.maplin.co.uk/av-200-start...he-mains-98007