Im in shanghai going shanghai - Harbin - Heihe -Blagoveschensk - Heihe by train.

I have 2 entrances to china that of course i used one already. I have Colombian passport that no need any papers to enter Russia. My question is when i get to heihe railway station..where do i need to go to buy the ticket to go to the other side and how much can it cost to cross the river to Blagoveschensk? i will go next week. And the other question in Blagoveschensk do they accept RMB or better change to Russian money? and also where to buy the ticket and how much does it cost in Blagoveschensk to Heihe. I hope is the same price.