how to express this idea

I made the following context to illustrate my inquiry:

Jim has a loan falling due, but he does not have the money to pay it for the time being. His banker knows this and tells Jim that he will talk to the director of the bank and ask for an extension for Jim. Here the banker says: "I will talk to the director, but I can not guarantee the outcome, so it is advisable you be minded to prepare the money".

By the underlined part, what I want to express is that Jim shall be prepared in mind to have to get the money to pay the loan (but not physically busy himself in getting the money, like borrow the money from a friend pending the bank's final decision) because he can not take it for granted that the extension will surely be obtained.

If what I say is not what I mean, could someone kindly help me find the appropriate expression?

Thanks,

Vincent