Can I Apply for the GC now or Should I Wait?

[AlexisA]

My wife petitioned for me using the I-130 back in March when she was a Permanent Resident (LPR). She, however, became a U.S citizen in July. The petition was subsequently upgraded to "immediate relative petition" in September 2013. My questions are: Should I wait for the I-130 to be approved before I file for the green card or can I file for it now since the case has been upgraded? Secondly, if I file for the green card now and the I-130 is denied later on, will my application fee be refunded for the green card?

Thanks for your help...