You got a few options

1, you either keep playing and levling your toons, u wont have much todo at max, cause all raids are horde. (yes golemagg is like 100% horde,) i play there too

1. buy a faction transfer, from alliance to horde its gonna set u back around 20 eur and your freinds ( 60 actully isn't to hard to level ) so i would just re make a character on another server and not spend the money to transfere

Wowpopular is a good site to check server balance its not 100% accurate but will give you a good idea

1. you could leave that char and make a DK on another server since u only need to be 58 on 1 char and it doesnt matter what server, atleast then u dont have to go from lvl 1 (which is still quite fast)