Try these for your tx. They act like lipo with very slow discharge if left for 1 year they will stil have 70% left in them. £9.99 delivered. bargin.
http://cgi.ebay.co.uk/8x-AA-2100mAh-...item35a9f0cac2
http://cgi.ebay.co.uk/TX-Pack-9-6v-N...item35a21667ba