Formula for returning value satisfying two variables

Request for a formula in Summary Sheet, Cell B4, B5, B6, B7 and B8 which will give respective value picked up from Sheets Region1/Region2/Region3/Region4/Region5 based on selection from drop down in cell D1 and D2.

For example : if D1=Region1 and D2=Apr-12, the values in B4,B5,B6,B7 and B8 should be 11,21,31,41 and 51 respectively
similarly if D1=Region3 and D2=Jun-12, the values in B4,B5,B6,B7 and B8 should be 15,25,35,45 and 55 respectively
similarly if D1=Region5 and D2=Feb-13, the values in B4,B5,B6,B7 and B8 should be 25,35,45,55 and 65 respectively

Regards