I'd like to put up a recommendation for Orli Stanoikov who provided an invaluable interpreting service to me recently. You can read all about it here:-
http://www.mybulgaria.info/modules.php? ... sc&start=0
As mentioned in the link, Orli is pretty organised and logical and, in addition, doesn't try to overcharge just because you are foreign.
He works mainly around Pernik (about 30km south-west of Sofia), (where there don't seem to be so many of us), but he also seems to travel into Sofia quite regularly in the course of his work. So if you need a good translator/interpreter and you're in Sofia, then Orli could be your man!
His contact details are as follows:-
Address: 2/3 Reno Street
Tel: (Office) (+359) 76 604878
(Mobile) (+359) (0)888 368782
Email: email@example.com or firstname.lastname@example.org