Like HD said, unfortunately those little self contained systems usually only work together. How invested are you with your current setup? We can help you put something together that would blow your current setup out of the water without breaking the bank. Need a little more info on your space constraints and listening habits if you're interested in exploring other options. If you stick with a soundbar I think they can get pretty pricey before you get into decent quality.
Just to give you an idea, these
DCM TP 160S' are very, very good for the price. They sound way better than they should for $83 a pair. You won't find any better at that price.