Take the tyre and tube off and then see if you can remove the rim tape intact. Then, the you should be able to find the end of the spoke that has broken off. Hopefully you will be able to get a replacement spoke but if they are factory built wheels you may be unlucky. Also, some spokes are only available in multi-packs which can be a real pain. Make sure you measure it well, and then measure it again prior to any order.
To refix the spoke should be an achievable task, you just need a spoke key and a bit of patience (pop the wheel on the bike, move one of the brake blokes close to the rim and then adjust until it spins true, don't forget to ping the spoke every now and then to check tension and I find that the odd squeeze of two spokes helps to even out things too).
Don't forget to put rim tape back on prior to tube/tyre. It can be bought at a very reasonable price if you need to cut off the old tape.