the best you can do is take an energy gel or drink(like SIS PSP22 gel), immediately before your workout. This will put energy into your blood stream.
It takes approximately 20-30 minutes for your liver glucose to be released in to your blood stream, so the energy drink will supplement this until it is in full flow.
Also i would do my cardio at the end of my weights or a separate day totally if poss.
If you do it at the end, the liver will be releasing its energy and the run will act as a warm down for your muscles and aid in recovery and reducing the lactic acid in your muscles. May also help reduce muscle soreness too.