Is it obligatory to purchase original software and redesign the database from scratch, or is it sufficient to complete the design with new original software to rectify the situation?

If you are able to seek permission from the company to use the pirated software, or pay compensation that satisfies them for their right, then there is no harm in benefiting from what you have already done and building upon it. Otherwise, it is obligatory to stop working with pirated software, because one of the conditions for repentance is to abandon the sin. If you use original software, you are not required to start from scratch, but you owe the company for your previous use of their software. Your mere intention to buy or pay the value when profit becomes available does not permit infringing upon the company's right. So, fear Allah, for whoever fears Him, He will ease their affairs, relieve their distress, and provide for them from where they do not expect, as Allah the Almighty said: {And whoever fears Allah – He will make for him a way out And will provide for him from where he does not expect}.