Air Realm — Terri J. Taber

Alicia Ravenwood was just a normal college student attending Oxford University when she started to have strange visions of her best friend fighting against an evil warlord in a magical land called Iriana. When she stopped going to classes her family admitted her to a mental hospital.
She was starting to let the visions take over her mind when her friend, Melissa Starr, found her and took her to the magical land she saw in her visions. Alicia finds herself in a land of magic, mystery, and love and she finds herself falling for someone she never thought she would and putting herself in danger in the process.
Now she must fight with Melissa, Jason, and Jonathan to find five elemental swords to cure Melissa's sister Dawn from the evil corruption inside of her.