Simple wordpress plugin - multisite

I am in need of a simple function to my wordpress website. This is a multisite install with membersites in folders. The only thing I need to get done is a plugin or a function to get the last post from the member sites to appear on the blogs front page. An exisiting plugin, Network latest posts, are able to get the title, but I need to get the title, the date, a small excerpt and the users gravatar, and of course link to the post. I have styled the output as I want it to be. To complicate a bit I want the output to be dived into two groups. I am using a plugin called Author Category where each user is determined to post in either category a or category b. I want one output with the latest posts from category a and one output for category b. If this ends up as a plugin I don't need to claim ownership to it, If it ends up as a function, then it is OK as well. I just want it to work.