Any h-bridge that can be driven with PWM should be suitable, assuming the voltage and amp rating is appropriate. You're not saying how many amps the linear actuator will draw. If it's a small amount (1-1.5 amps) then an Arduino board with a "motor shield" will probably work okay.
The other question is how to integrate it with MSRDS. That's an end-of-life product, so it's hard to find drivers or adapters for anything you can buy on the market today, but if MSRDS can write to a serial port, it should be able to write to an Arduino board.
If you need a higher-power motor controller than a "motor shield" then a Sabretooth controller, or a Pololu high-power motor controller, could work, and can still be controlled from an Arduino (which should in turn be controllable as a serial device from a PC.)
