Homepath oil leak during closing

[Dave Smart]

I am in the process of purchasing a homepath property and discovered a pretty significant leak in the oil tank today. I am positive there was not this much oil on the basement floor two weeks ago when I viewed it, and there is another 3/4s of a tank left. By the time I close I am worried I will have a serious issue on my hands. Can anyone give me any advice on how to handle this, as I have another three weeks left until closing. When notified the selling agent said he will put down some quick dry and a bucket, but I believe this needs to be monitored more closely if it is not properly fixed. 

I expect to pay for the tank replacement and clean up, but this is an urgent issue and I am wondering how to resolve it before it gets worse in the next three weeks.