I'm not going to go to an external site to look at your code, so I'm posting the generic solution.
Just use a normal form upload for your file.
<form action="@Url.Action(" uploadaction="," uploadcontroller=")">
<input type="file" />
<input type="submit" value="Upload" />
</form>
Then in your controller:
public ActionResult UploadAction(HttpPostedFileBase file)
{
}
Information on the HttpPostedFileBase can be found at:
HttpPostedFileBase Class (System.Web)[
^]