The machine you have there is almost the lowest of the lows when it comes to performance. Just stepping up to a hypertherm powermax 45 will yeild impressive results for you without breaking the bank. They aren't HF which means no interference with your computer and still have the pilot arc.
The HD machines are a completely different animal and in a completely different price bracket.
Jim will probably chime in and give a better answer (hopefully even put up an edge shot or two)