Your sound card has a Line in, (usually the blue one). Plug the mixer to it. The mixer should have an ear phone out. You do not have to get a mixer with a powerful pre amp. Get a low range mixer without a pre amp.
Plug your dinamic microphone to the mixer.
There are some sound cards with 6 jacks. Those have more features. But if you have a good mixer, you can stick to it. If you mix offline, it is not possible to digitally master and non linear multi track editing. If you wish to do digital mastering and multiple track non linear editing, get a better sound card and don't spend for a mixer...