1) "The literal meaning of the word bastard is the circumstance of being born of parents who are not married to one another (see illegitimacy). The word is also used as a generic derogatory term for a male who is rather obnoxious or unpleasant (a derogatory word for an obnoxious or unpleasant female is bitch)."
Source:
http://en.wikipedia.org/wiki/Bastard

Further information:
http://en.wiktionary.org/wiki/bastard


2) "A Muslim (Arabic: مسلم) is an adherent of the religion of Islam. The feminine form of 'Muslim' is Muslimah (Arabic: مسلمة). Literally, the word means "one who submits to God)"."
Source:
http://en.wikipedia.org/wiki/Muslim


3) Saying "muslim bastard" wird generally be understood as an insult apllied to an adherent of Islam. It is discriminative against muslim. It is not racist (whether "bastard" nor "muslim" have something to do with "race")

Further information:
http://en.wikipedia.org/wiki/Racist