You know, if you like it, play it! The one I played was a nice feeling guitar, though I didn't crank it up.
I'd price out changing all the hardware and the wiring. Do you have a good guitar repairman? In the USA, the parts would cost you $200 for a nice set of pickups, the pickup selector switch, good wiring, potentiometers, jack plug, tuners, etc. In fact, the tailpiece and tuneamatic would probably make the price go a lot higher.
Man, if I had to do it a little at a time, I'd change the jack plug, then see if you can find some saddles that will fit that bridge that weren't made out of pot metal. I would be really gentle with the potentiometers, because they'll probably wear out quickly. The pickups sounded okay, maybe they should stay for a while. Be careful with the screws when you change parts that are screwed into the body. I think that maybe part of the problem is that part of the body is made of cheap laminate and the screws holes can get messed up easily.
Good luck, we've all bought things before that we shouldn't have. Welcome to the Club, Russian Guy!!!
Regards, Harry