Legal status of Visara Pawti(Document for Token Money)

Sir,
My father in law has a residential plot of 3000 Sq.Ft.at Rahatni,Pimri,Pune.In Oct.2008 I on behalf of my Father in law executed a Visara Pawti on stamp paper of Rs.100/- for accepting Token Amount of Rs.50,000/-with a prospective buyer.As per instructions of the buyer I did not deposit the cheque till today.He told me that he will pay that amount later at the time of agreement.In the document it was mentioned that I agree to sell the land after completing the required legal documents like Gunthewari etc for the execution of sale deed.I was told by the buyer and his agent that Gunthewari system is opend by the Govt.Later on I found that Gunthewari cannot be done as it is not opened as yet.I have other documents like 7/12,Ferfar Utara,IndexII.Original Purchase agrrement,Zonal certificate etc.The Buyer is insisting on Gunthewari document,which is not possible at the moment.Iam trying to get city survey document through city survey office.I have following questions.
1.What is the legal status of Visara Pawti?
2.As I have not deposited the token money,although in the Visara Pawti it is mentioned that I have received the amount,can the Visara pawti binding on me?
3.For how long is the Visara Pawti valid,as no mention is made of validity date.
4.If the Gunthewari system is closed and the buyer refuses to do the sale agreement
What are the options available to me?
5.Can I sell the land to other buyers without the consent of the first?
Please advise me as to how to get out of this problem.The buyer has orally said that he will purchase the plot after City survey is done,but I do not trust him.
Please advise.