I am trying to predict future values using 2 data sets.  I'm not sure if
Forecast is the right function or if something else is better suited for
this.  My situation could best be illustrated using this simplified example.

I have 2006 data for weeks 1 thru 6.  I'm trying to predict future 2006
values for weeks 7 thru 13.  I alse have historical data for weeks 7 thru 13
from last year (2005).  I would like to predict weeks 7 thru 13 this year
using the preceding 6 week time frame, but also want to use the corresponding
time frame from last year to factor in the appropriate seasonality trend.  

Can someone point me in the right direction as to how to set this up?  Below
is my attempt at drawing out the data that I have available to use.

           wk1     wk2.....wk6     wk7       wk8......wk13
2005                                      9           8          10        
2006     10        11       13        ?           ?           ?

Thanks,

Jeff