What kind of popup are you using? Another window or a hidden div?
I would hope the latter since that wouldn't be blocked by your browsers popup blocker.
you could then just call (check this I could be wrong.)
parent.refresh();
if it's the former.
window.opener.location.reload();
attached to your onunload event of the child window.
Personally I would roll something using jquery and use an ajax call to call the specific method to rebind your gridview.
This would get you started.
http://api.jquery.com/jQuery.post/[
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