Update Records Just Selected (in One Query)

I have a stored procedure that I give some parameters and it joins a couple of tables and returns the results.  I would like to know how to update the records in one of the original tables before returning results.

CREATE Procedure dbo.DS_GetSomething(
@someValue char(5)
AS

Select table1.* ,table2.* FROM table1 left inner join table1.itemid on table2.itemid where table2.someValue = @someValue

The table has a field of IMPRESSIONS that I would like to do something like:

;UPDATE table1 set impressions=impressions + 1 where recordid=??

I don't know how to access the recordids I just got from the original select statement.

Thanks for any help

Greg