The usual time frame for receiving a Refund when there is a Form 8379 filed is 6-8 weeks. I have seen it come quicker, but I have also seen it take longer.
Also, for future reference, it is more efficient to E-File Form 8379 along with your Tax Return rather than mail it separately.
Check out the TurboTax FAQ below for more information:
https://ttlc.intuit.com/replies/3326788
