I recommend that we take this info with a grain of salt but here's what said on the matter:
“Despite all the rumours to the contrary, the role of Gwen Stacey – Peter Parker/Spiderman’s love interest in Spiderman 4 will not be played by Emma Roberts. Andrew Garfield will be locking lips with the lovely and talented Irish actress Dominique McElligott. Dominique received word on Friday that she landed the role and was thrilled to hear the news. Can’t think of a better choice as she is not only beautiful and charming but a phenomenal actress and definitely one to watch in the coming years.”
Sweetre15: Anyway,I think she's got the looks and some say she's a good actress but does anyone know anything about this chick ?(Not that it matters that much) because IMDB doesnt even know her age or anything
http://scifimafia.com/2010/08/rumor-has-it-dominique-mcelligott-has-already-joined-the-cast-of-spider-man-as-gwen-stacy/