Can't see on the picture of that mobo on Epox's website what it looks like. You may be able to solder that clip back on if you are good with a soldering iron. You will need to scratch the chromium off before you solder, but I doubt it will hold, let alone be strong enough to hold the battery in place. Instead, look around for a plastic battery-holder with wires, that you could solder to the mobo where the battery was. If hard to find, look for a cheap digital clock in e.g. a car-accessory shop, these run on the same type of battery. With a little DIY you should get it up and running again.