Any way to check on the status of my green card renewal?

I sent the I-90 by certified mail so I know that USCIS has received the application. I am waiting for my notice for my biometrics appointment. Is there any way to check on the status of my application? We are waiting with our vacation plans to avoid conflict with the appointment date. I thought that I would receive a notice within 2 weeks of receipt of my application... How long does it usually take?! And how many days/weeks is the biometrics appointment from the time the notice is sent out?