Thanks for your reply.
Well, the only way you get back the whole of the property is if your sister in law agrees to do so. If she is willing to give up the half share, a Deed of Variation to your Husband's Will can be prepared and signed at anytime within 2 years from the date your Husband died.
A Deed of Variation is used to changes the terms of someone's Will post death.
Therefore, a Deed can be prepared to show that your Husband's half share in the property passes to you.
Your sister in law would need to sign the Deed, and then you would become the legal owner of the whole of the property.
I hope this assists and hope that your sister in law will be willing to co-operate. You may want to agree to leave half of the house to her in your Will, to make this happen.
If I have helped, I would be grateful if you could rate my answer.
If you have any further questions, please reply to me on this post, rather than asking a new question.