Another option if you don't mind spending cash that is well worth it is:
This one requires that you sell your current Drives (unless they are AC).
Find out what your KW's your motors are, then goto Automation direct and get a "Sure Servo" System with AC dirves, you won't be disappointed, super, duper accurate!!! and fast!!!
A 1kw (1000watt) approx, 42in/lbs A/C servo Medium inertial system is about 1500/axis.
A 750w (1 horse power), system is about 1K per axis.
Prices go down as well if you choose "Light inertial systems"
The drives take a Step and direction signal, and have several other I/O options and perameters. These Drives will easily sling around a Haas VF4 or a Hurco.
Other wise what Chad said above is true.
Scott