She wants to become Muslim but she does not know where the qiblah

Firstly: 

We congratulate you on reaching the right decision and coming
to know the true religion. We ask Allaah to help you and increase you in
faith, happiness and contentment in this world and in the Hereafter. 

You have to bear witness to the truth, and testify that there
is no god except Allaah and that Muhammad is the Messenger of Allaah, in
order to enter this great religion. Do not delay that for a single moment,
so that you may be recorded with Allaah among the blessed victors. Even if
you do not know the direction of the qiblah, enter Islam and ask about the
direction of Makkah, for that is the direction of the qiblah. This is
something easy to find out in sha Allaah. Even if we assume that you do not
find out the direction of the qiblah, try your best to find out which
direction is most likely, and pray facing that direction; your prayer will
be valid and there will be no sin on you. 

Go to the nearest Islamic Centre and they will help you to
learn Islam and will give you the books that you need, in sha Allaah. 

Secondly: 

You can use a compass or some watches or other things that
are equipped with a compass, or a map of the world, in order to find out the
direction of the qiblah. 

By looking at a map of
the world you will see that the direction of the qiblah for those who live
in Britain is South-East, so that is the direction you must face. A slight
error in direction for those who are far away from Makkah is forgivable.

And Allaah knows best.