A 5.1 Surround Logitech solution for roughly $75.00 will fix your issues on a budget. You will need some extension cords for your 5 satellite speakers if you have a large room to place them at.
It has worked for me with my PC setup in a large office/bedroom size room, and my brother's large family room with a 50+ inch TV at his house. I've heard comments from some of my brother's friends about how 'ghetto' his setup looked, but praise about how good it sounded.
A proper setup, (home theatre quality), like Defron said can cost a grand easily. And that is shopping on a budget too.
Soundbars are a pretty looking gimmick for their price.