According to Charice's Twitter Account, She will not be on Episode 7: The Substitute
Normally, Charice would say "Definitely, Sunshine Corazon will be back! Just watch the whole season!" Charice tweeted this after episode 6 was shown in the US. She probably thought GLEE just aired episode 7 that is why she answered "no." Oh well, let's just wait and see if Charice will be on Episode 7 or not.