Ok, so it seems that my bm (who, btw is also my FSIL) has been loosing weight like crazy for her wedding (in August...b-ioch...lol, jk) -- additioanlly, I called the store and they said the top is sized a little big in these dress (it's got an imperial waist - this being the main cuase) so all in all they said that b/c of the shape/waist of the dress it shouldn't be a problem to bring it in...but she can't loose a tone more weight b/c it can really only sucessfully be brought in about 3 sizes.
...so hopefully that little hurtle is fixed! Thanks ladies for your words of wisdom!