Is it possible to have a plugin for when some one donates thier go into the system and we set the usergroup to end in 31 days fo rsay
Usually donations need verification, so I'd suggest you create a user group called "Donators" for example, and then once you verify that a user has successfully donated to your website, you change their group.
No I want a plugin that you put the user in for say 31 days then after it it takes them out
The only plugin that I know of off the top of my head, is MySubscriptions (and that's if I'm following your request correctly).
You want a plugin that when one sends money to you, it places the user in a usergroup for a set period of time, correct?
You can find information on this plugin
here. Beware, that it is a paid plugin.