You are entitled to receive the whole sum and then calculate the interest
to give away in charity as it is considered Riba (usury). May Allah give you of His bounty, grant you a better reward and assist you to fulfill your needs. Allah says,
And whosoever fears Allâh 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. And whosoever puts his trust in Allâh, then He will suffice him.
May Allah grant you success! May peace and blessings be upon our Prophet Muhammad, his family, and Companions.