Index / Match across multiple columns

Not sure if I have the title right. Here's what I'm looking for.

Columns A to G contains days of the week formatted to show only the DD. Column H is the week number and may not follow standard convention. I need to input a date in Column I and have it look up the date in columns A to G and then return the week # from Column H into Column J.

Index/Match formula as I know it is limited to indexing a range, then matching to a column in that range. Need a formula to search the entire range - A2 to G54 (or so) and return the week # from Column H.

M T W T F S S Wk# Input Date Wk# (result)
30 31 01 02 03 04 05 1 01/08/14 2
06 07 08 09 10 11 12 2

Thoughts?

If the cells really do contain the full date (eg, year+month+day) formatted to only display the days,
AND
the cells increment calander-like so that it increments across and then the first column in the n+1 row is the day after the last column in the nth row;
AND
the dates are in ascending order, eg they increase as you go down row-to-row;

Then you can actually solve this with a regular index(match()); just use a MATCH(,,1) instead of a MATCH(,,0); guarantee it will find the row below it by knocking one day off the lookup date, and then add that row back in the index. That should just about do it, I think.

J1 = INDEX(H1:H100, MATCH(I1 -1, G1:100, 1) +1 )

Mmmm....maybe I'm not quite getting it. And I should have attached the file to start with. Here's the file I'm working with.

EXCELLENT! Makes it easy! Either of the last 2 works just fine. Thanks Ben for your help!