list category posts

I have a few categories set up, I am looking to have a “sidebar” dropdown on each category template page that would allow the user to pull up the posts from that category by month.

Results Category Page – Shows the newest posts from Results Cat
In the sidebar a drop down “select Month”
User can choose month to view posts only from that month.

I have 3 category templates for the 3 different cats, these act as “sections of the site”

Results
News
Reports

I am using currently the “archive.php” file with a bit of code to get the news posts in a sidebar drop down. When a month is selected is takes the user to the archives page, I then have a piece code which only shows posts from the News Category. I want to do this for the 3 different categories. would be cool to be able to have 3 different archive.php pages that pull the posts from each category.