Willsenton vs Billie MK 1

Take the money you have double it then look for a new amplifier. Basically going to be a lateral move in equipment. You will definitely get a different sound, but are you going to think that it is better? You are more likely to get a yes if you use the above advice. Good luck in your journey you are starting on some good feet 👣. 

if you get a chance, please create a virtual system so others can see and give good advice. Until then, I will ask these questions in the dark. Do you have a subwoofer? If that is a no, I would look at that first because your Billie has good power for those 87db speakers of yours. With that being said when it comes to tube amps others on this site can give you much better advice.