Dear Donald, 

In answer to your question, I am supposing you are entering a religious institute that requires complete renunciation of material goods. My answer is taken from the Code of Canon Law, 668, §1, 4 & 5. 

Concerning a religious institute that requires complete renunciation of material goods the following holds: you "are to make a renunciation before perpetual profession in a form which, if possible, is also valid in civil law and takes effect from the day of profession." From the time of your perpetual profession, you "lose the capacity of acquiring and possessing, and therefore invalidly place acts contrary to the vow of poverty. Moreover, those things which accrue to them after the act of renunciation belong to the institute, according to the norm of proper law." 

This would mean that once you have made your perpetual profession you can no longer possess nor administer any material goods. The vow of poverty means total renunciation. The savings would, in the light of Canon Law, pass to the religious institute of which you are a member. You would not be able to decide how to use it. 

Nevertheless, the first paragraph of the same canon, stipulates that if one is joining a religious order that requires complete renunciation, "Members are to cede the administration of their goods to whomever they prefer before first profession, and unless the constitutions state otherwise, they are freely to make disposition for their use and their revenues. Moreover, they are to draw up a will, which is also valid in civil law, at least before perpetual profession." 

In your case, because the savings already belong to you before joining, you ought to make a will before your first profession that would hand over the savings to another, which could be your religious institute, if it is allowed to receive such gifts according to its own norms.