The Orange with the three band eq is pretty much a Fender style tone stack, but the gain is different so they end up dirtier. Don't think the power stage is that similar, not sure but some Fender stuff ran in Ultralinear. A lot of colour/limitation is going to come from that cab though, is it one of the pyramid baffle ones?
If you have money to chuck about, probably can do better than Orange, basically, Matamp.
If all you need is more volume and like the tone of the amp, a better cab is the way, Barefaced Super15 will be lighter, louder and lower than the cab you have, but might not offer the same cab colouration.