Hmm, I doubt it. Not if it hasn't been built to use one.
The system would need an Infered attachment for one thing to understand what is coming from a univeral remote, and it probably doesn't have one.
It would be rather impossible, without being really electronically minded, to set one up...especially if those dials controlling volume on that speaker are analog controlled...
I guess though, you could open that right speaker up. Find out how that right speakers dials are attached, and take the circuit board or whatever, and drag it along a wire so its able to be closer to you...
I'd advise to give up that idea as a no go though
As long as that speaker is near to you anyway, since its the Right, theres no real issue I don't think.