being able to select a varying numbers of colums from a formula using a macro

I AM USING 2 DROP DOWN VALADATION CELLS ON A PAGE SAYING I WANT TO SELECT A PERIOD OF TIME FROM A DATE TO DATE. THIS THEN LINKS to AN IF STATEMENT ON ANOTHER PAGE, WHICH SAYs THAT IF THE VALUES ARE EQUAL AND OR GREATER THAN ETC, ENTER VALUE 100 IF NOT ENTER 0. tHEN I AM COPYIMNG THAT WORKBOOK TO A BLANK WORK BOOK AND SORTING the entire workbook by that row decending so i get the first date i have selected in the coloum A. the trouble im having is the period i have selected could be 1 to 256 days long and i want to only pick the days i have selected with the 100 in. i know where there first coloum is it is a, but i do not know how the find the last i have selected, using a macro.

the ctrl right does not work as that goes to the very end because it scans via formula, nor does the paste special values, then ctrl right as it goes to the end again.

Any ideas?