I would look towards getting a 5W or lower powered valve amp. Even at 5W, you'd probably not be able to crank it.
I recently fitted a high efficiency Peavey Sheffield speaker in place of the stock Fender speaker in my old solid state Fender Princeton 112 Plus (also 65W I believe), and now I can't turn this up beyond 1/10 on the volume or it's too loud at home!
Of course, it's not a patch on my 120W 5150-II (quad of 6L6s), which would cause structural damage at 1/10 at home :D
If you want great tone at low volume, master volume (mentioned above) is your friend, as is a LOW power valve amp, something like 1W maybe..., also a fairly low efficiency speaker. Don't look towards traditional 'metal' gear - it's mainly aimed at low-breakup, pre-amp based distortion, with power amp distortion only happening at deafening volumes, and speaker breakup essentially never ever ever happening.
Changing the speakers on your existing amp WILL make a big difference (although not necessarily as nice a difference as switching to a valve amp). I found my old fender amp became MUCH more 3-dimensional sounding, with a nice midrange bite and grind when I put in the Peavey speaker in place of the fender speaker. Also handles the low stuff much nicer. It's difficult for me to suggest anything for you, because my requirements are very different from yours!
Blackstar HT5 is a pretty good call, I can't offer any other specifics, because I'm personally into the big beefy stuff for gigging in a hardcore/metal band :)
Good luck, and welcome to the forums!
Roo