for tv, i couldn't give you an answer. i guess if you have an amp then it should be fine.
for computer wise, you just need a decent audio interface, which i assume you already have.
decent monitors on a budget, the Behringer's are quite ok. you could probably get decent ones in their range for 500 bucks. they do the job if that's what you're after. if size doesn't matter then you should be able to pick up some 4" ones pretty cheap
until