Index / match functions

Is anybody able to assist me please. I've never posted in this forum before but i've found it very useful to see threads already posted.

Basically I want to bring back the result of "Mar-13 into cell A2. The result being the month that data on line 5 was less than 0.

A B C D E F G
2 #REF!
3
4 Sep-11 Dec-11 Mar-12 Jun-12 Sep-12 Dec-12 Mar-13
5 500,000 500,000 500,000 500,000 500,000 500,000 -800,000

I need to avoid changing the order of the info ie not using a hlookup.

I was trying =INDEX($A$3:$G$3,MATCH(A7,A4:G4,FALSE),1) where A7 was -800,000 to no avail.

Any assistance would be appreciated.

Tx

helpppplease