I wonder if it may be less hassle going with a KB Electronics controller, maybe something on eBay? I don't know enough to recommend a model for you but they make good stuff... here's one you could chase down specs on:
New KB Electronics Inc. KBIC-120 Motor Speed Controller - $25.00 + $7.15 Expedited Shipping
http://www.ebay.com/itm/New-KB-Electronics-Inc-KBIC-120-Motor-Speed-Controller-/131396049497
The controller runs this:
New KB Electronics Inc. KBIC-120 Motor Speed Controller - $25.00 + $7.15 Expedited Shipping
http://www.ebay.com/itm/New-KB-Electronics-Inc-KBIC-120-Motor-Speed-Controller-/131396049497
The controller runs this: