help with HT setup?

I have completed my 2 channel setup and am ready to update the HT portion of the system. I have CJ 2 channel amp and preamp. Pre has a processor loop in which is plugged an Adcom GSA-700 which is a 3 channel amp with pre-processor. The Adcom is pro logic and needs to be replaced/upgraded. Adcom makes a GDD-1 which is a Dolby digital decoder which upgrades the GSA-700. However it does not have DTS (is this important?). Is there another product similar to this with DTS which will allow me to use the GSA-700 or should I get a HT receiver and use the amp of the receiver to drive the center and rears? If I use a receiver, how do I tie the CJ equipment and receiver together? Would I still use the processor loop of the CJ as I do now? Your suggestions are appreciated