insufficient, in sufficient

Insufficient or insufficient ( one word ) means not enough; lacking what is needed or required--
The case was dropped due to insufficient evidence.
The check came back marked "insufficient funds".
This answer is insufficent; you need to show your work.

In sufficient or in sufficient ( two words ) means [in] enough or adequate quantity or number--
The customer wants to know if we can produce these widgets in sufficient quantity.
If the marchers turn out in sufficient numbers, the press will be sure to take notice.

Now that you know that, you can say--
"Our funds are insufficient to cover expenses, unless we get donations in sufficient quantity to make up the difference."