It appears I'm looking for something about as common as the holy grail, but bear with me. Up til now, I play acoustic and sing into my Alesis firewire 8 mixer, listening through headphones

I wanted to make some noise, but also want to be able to start playing a bit of electric. I've recently purchased a Spider III 75 amp and am having a lot of fun with the electric guitar. Definitely a fun amp for the beginner who doesn't know any better!
I have routed my mixer into the CD input of the amp so that I would not inherit any of the amps effects on my already mixed acoustic and mic sound. It sounds pretty good, although I need to dial the mixer in a bit more. I have to admit that the sound is better through headphones than it is through the amp, but it ain't too bad.
The question is this: Is there a good all-purpose amp/pa/?? system out there that would fit the bill better than this amp? Something to give me the awesome acoustic/vocal sounds that I do the most and allow me to have fun with the electric? I understand that having more than one piece of equipment may the route I have to go, but one piece would be better financially for me most likely!
Please help!
cmadsen