You will need to use a combination of PROC TRANSPOSE, after separating current period observation into a separate file, perform the transpose, and then merge the two files back together. I suspect you can use PROC PRINT for generating the horizontal observations having 'week period' and 'month period' variable values, as generated by PROC TRANSPOSE.
Review the PROC TRANSPOSE documentation with reference to the BY and ID statements and the PREFIX= parameter. Also, for PROC PRINT, you will want to explore using the VAR statement and employ the use of a "stem variable prefix" ending in a colon character allowing you to abbreviate your variable list.
The other option is to use a DATA step for full-control with PUT and column-position report generation.
Search the SAS support
http://support.sas.com/ website for SAS-hosted documentation and supplemental technical and conference topic papers.
Scott Barry
SBBWorks, Inc.