Does anyone know where Lyudmila Poleshchuk is now, from Belarus Brest, moved to moscow.?

I bet finding her would be like trying to find a needle in a haystack. Your best bet is to try to either contact her family, contact mutual friends, or contact the American-owned company in Moscow and figure out if she still works for them. But if it's been 4 1/2 years since you've been in contact, I think it would be very difficult to figure out where she is in the world.