[MovedGoalPosts]

Short answer, no. If you have broadband via modem, you can't have broadband via Set Top Box. Indeed broadband via Set Top Box is becoming less common and is only now for customers that have previously had internet this way, usually only in some ex ntl areas.

Is there any way you can run an ethernet lead from the Belking router to the PS3? Alternatively you could perhaps add an additional wireless point to you network to act as a signal booster. Maybe you could consider the homeplug solution?