Aluminum Brace / Bracket

grabcad

Anyone have any suggestions on how to increase this bracket's strength? The requirements are below: My goal is to design a bracket out of a 1x6x12" block of 6061 Aluminum Alloy that weighs less than 10oz. The top plat must be 1' across and .125" thick. The support holes at the bottom are where the bracket will be mounted and crush tested. These holes must measure 1" and be 10' across. Finally from the top of the flat plate to the center of the holes must be 5".