I had a Shopbot CNC similar to what you described.
Our dust collection system used the smaller HF dust collector that we wall mounted w/ a cyclone (take your pick, DustDeputy is a proven performer), upgraded filter and appropriate diameter hard and flex tubing.
Worked well enough for the low entry cost.
I think your biggest concern after installing a DC is the shroud around the router bit, that is where you will loose the most performance. Lots of DIY solutions, some store bought as well.
Good luck.
PS the big gains of the cyclone are minimal bag changes, a definite advantage when milling out lots of material like CNC tend to do.