Cheapest way to connect to tv...but still use computer

I don't have cable so am starting to watch stuff through my MBP using apple's adapter to go to my tv.

However when I send it over to my tv I can't use my computer. Is there anyway around this?

Are there other options if I want to put content onto my tv through the internet, while having access to my computer? Either by using my mac..or getting another device?

Without delving into it here full on have a read of the Sticky bobtomay wrote about Connecting your Mac to your TV. Read it the whole ways through as it is very intuitive.
If you still havnt seen what your looking for pop back here and ask more specific question

TM