ps: hey, only 'cause you're studying italian, let me correct you about a thing: the correct verbe that is used to say that you play an instrument ain't "giocare", but it's "suonare"... so, your sentence becomes:
"bella ragazza italiana che suona il basso"
Sorry for the correction, but I only thought to tell you, so that now you now it.
Oh, and thanks for calling me "bella"!