R coding / advanced data / fix

I have a very large dataset with four variables: "ID", "Date", "Var1", "Var2" The dataset is organized in the way that ... ...row 1 contains for ID 1 and the first date both variables var1 and var2 for that date, and... ... row 2 contains for ID 1 and the first date both variables var1 and var2 for that date, and... ... ...row n+1 contains for ID 2 and the first date both variables var1 and var2 for that date, and... etc. I need to compute two things. 1) I need to compute a moving average for each ID for each date over the last 30 days of var1. 2) I need the variance for each ID for each date for the time [-60; -30] days prior to the focal date for var2. Please apply only for this job if you can do this easily. I need it ASAP (next 8 hrs). Sample data is below. "ID" is "cusip", var1 is "vol/shrout" and var2 is "prc" date permno vol cusip shrout prc 2000-01-03 10001 1721 36720410 2450 8.5625 2000-01-04 10001 1080 36720410 2450 8.4375 2000-01-05 10001 1711 36720410 2450 8.5625 2000-01-06 10001 580 36720410 2450 8.5000 2000-01-07 10001 1406 36720410 2450 8.4375 2000-01-10 10001 3390 36720410 2450 8.4375