Olga is one of those names that is beautiful when said by a person of the names origin (pretty much anything but English in this case) but awful in English. I've only ever heard ol-GUH in English and that just isn't correct.
I like these best:
Olga AriadneOlga CecilyOlga Daphne Olga DorotheaOlga Felicity Olga Juliana Olga Juliet Olga Leontine Olga Miriam Olga Zénaïde