All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
We have already issued Fatwa 86001 clarifying that Ribaa (interest and usury) is forbidden whether in a Muslim country or a non-Muslim country. Therefore, it is not permissible for you to buy the house using Ribaa except in a situation of dire need, and there is no necessity in your case since there is an institution through which you may buy the house without committing the great major sin of Ribaa.
Even though the percentage which this institution takes is high, yet this is not a sound reason for dealing with institutions that deal with Ribaa.
For more benefit, please refer to Fatwa 88238.
Allaah Says (what means): {… And whosoever fears Allaah and keeps his duty to Him, He will make a way for him to get out (from every difficulty). And He will provide him from (sources) he never could imagine.} [Quran 65:2-3].
Allaah Knows best.