If your Xbox is too far from your router/computer to string an ethernet cable temporarily, people have gotten their Xbox online by internet connection sharing with a laptop, bringing it to a friend's house, etc. If you have a home network and either an old router left after an upgrade or can get your hands on a cheap wireless router, you may be able to turn it into a gateway to connect your Xbox to an existing network (check the options, or see if it is compatible with third party firmware).
Alternately, if there were no changes made in the save format you may be able to email email@example.com with your save (see Lar's post here
), and have them perform the summoning, save and return it. Even if the patch didn't change anything in the saves, there may be other cutscenes that have a problem if you take a long time to reach those points.