So I kind of have a problem...
If the new DLC, Dawnguard, has to mainly deal with the Elder Scroll, and I accidentally "sold" my Scroll to Urag gro-Shub at the College of Winterhold library, how could I possibly even complete the DLC?

If you have any possible answers, please reply to this thread, 'cause I really don't want to spend money on something I can't even complete.

Thanks

There are an unknown amount of elder scrolls in the game world.

So it's likely it's a different scroll.

There's more than one elder scroll in the universe. And I doubt the DLC will use the exact same one. They wouldn't have give the option to sell it if they intended to use it again.

The Elder Scrolls title is plural so there is more than one, likely not that one as it is quite far in the main quest which a few people wouldn't have yet.