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.
What we understood from the question is that you promised your wife when you sell the flat you will give her some of your properties and this did not happen until now. This is just a promise of a gift and you are permitted to go back on your promise because of what you mentioned.
Moreover, a gift does not become effective unless the other person possesses it, and in your case, it was just a promise of a gift, so you are permitted not to fulfill that agreement for the reasons that you mentioned, like the sickness of your wife and that she forced you to sign under unusual circumstances when you were not able to refuse her demand. In addition to this, she insisted on divorce and separating from you, although it is forbidden for a wife to ask her husband to divorce her without a sound reason, like due to the harm and the like.
However, it is permitted for a husband to take back his wife as long as she is in her waiting period from a revocable divorce and it is not a condition that she agrees to this as Allaah Says (what means): {And their husbands have more right to take them back in this [period].}[Quran 2:228]
Therefore, you may take her back before the expiry of her waiting period if you like, as regards the promise to give her some money, then you can break your promise since the situation is as you mentioned.
Allaah Knows best.