Gosh it's been so long since I have played Oblivion brings back memories
Anyway, with the bit of information you have provided and doing some quick research on the internet, I believe the quest she is on is called "Breaking the Siege of Kvatch" you should be able to check your journal to verify that. Below is a quick walkthrough of the quest taken from this website:
http://elderscrolls.wikia.com/wiki/Breaking_the_Siege_of_KvatchQuote
Reaching Kvatch
At the base of the hill of Kvatch, speak to one of the survivors. The Hero learns that the few remaining guards are still fighting near the city gate. Head up the path to eventually reach three guards and their captain, Savlian Matius, an imperial. He will say that Martin, the heir the Hero is looking for, is trapped inside the city, but he can't come out until the Oblivion Gate has been shut and the courtyard cleared of deadra.
Oblivion Gate
Enter the Kvatch Gate; inside is a hellish world filled by lava. A surviving guard, Menien Goneld will explain how to shut the gate. He explains the the nearby Sigil Keeper has a key to open door to the Sigillum Sanguis. inside of that is the Sigil Stone that keeps the gate open. Remove that and the gate will shut.
Back at Kvatch
Head back to the Captain and speak to him. He will congratulate the Hero and then ask he or she to enter the burned-out city on a rescue mission. There will be a few more Daedra in the square beyond the gates which the Hero and their companions must kill. Once the coast is clear, enter the church where the captain will evacuate the survivors.
Next step
At this point, the Hero can speak to Martin Septim to continue with the main quest by taking Martin to Weynon Priory, or continue with the optional second part of "The Battle for Castle Kvatch" by speaking to the Captain.
If you are still having some trouble here is a video walkthrough of the quest:
http://www.youtube.com/watch?v=BF00MI%5FNnkk - Part 1
http://www.youtube.com/watch?v=1yMfE07H6N0 - Part 2
Let me know if it helps and if you have any additional questions
This post was edited by RatM on Feb 1 2013 01:54am