A good ext. cab would help, esp. in that you could point it in the direction you need to better hear yourself. I had the same problem yrs. ago, and often by adding another cab and "surrounding" yourself you can add alot of "your sound" to your own space. I used that to great advantage back then, you'd be surprised what one more speaker cab can add. Adding a gain pedal, for ex. the BBE Boosta Grande, can help also, providing you need dB's and not strictly gain, it that makes sense. What I mean is, if your amp is dimed, and clean enough at that volume, a clean boost will add dB's and help you cut through the mix. I would try before you buy, to see if it helps. But I would definitely try an ext. cab. A 2x12 cab can be lightweight and really kick out some serious extra sound. I can carry my Avatar cab w/ 1 hand, and it puts out some unreal volume w/ the Valve Jr. With my Traynor YCV 40, it is a window shaker.
Other than than that, maybe a bigger all valve amp.
I don't know how much more volume you're talking about.
Guitars
Wilburn Versatare, '52 FrankenTele(Fender licensed parts), Fender USA Roadhouse Strat, Fender USA Standard B-bender Telecaster, Agile AL 3000 w/ WCR pickups, Ibanez MIJ V300 Acoustic, Squier Precision Bass,
Amps
Ceriatone Overtone Special, Musicman 212 Sixty-Five, Fender Blues Jr., Peavey Classic 30, Fender Super Reverb, Traynor YCV-40 WR Anniversary w/ matching 1x12 ext. cab, Epiphone SoCal 50w head w/ matching 4x12 cab (Lady Luck speakers), Avatar 2x12 semi-open back cab w/ Celestion speakers
Pedals
Digitech Bad Monkey, Digitech Jamman, DVM's ZYS, Goodrich volume pedal