Hi. The IG42 WiFi robot can be found here
http://www.superdroidrobots.com/shop/item.aspx/4wd-wifi-controlled-mobile-robot-ig42/1222/
There are a lot of different battery options at the bottom of the page. The fun time will really depend on how its driven. If you are racing all over the place and spinning around in circles in deep grass you will be drawing a lot more current than just sitting there. So its really hard to give a number. If just sitting there with light driving you should get 4+ hours with the standard batteries. You can upgrade the batteries if you want to do heavier driving or want more run time.
The range of operation is just standard WiFi. depending where you mount your router, etc. will depend if it can make a 1200ft drive. You can also install repeaters and access points. A easy way of testing is if your smart phone or laptop can get a wifi signal at the end of the drive, the robot will too.
For additional WiFi Robots please visit:
http://www.superdroidrobots.com/shop/category.aspx/wifi-robots/90/
For our WiFi support page please visit:
http://www.superdroidrobots.com/shop/custom.aspx/wifi-robots-overview/14/