she will have probably picked them up off your other cat you need to treat them both ,yes they will bite you but dont panic , get some frontline treat the cats the fleas wont live on you they will just hop on you have a meal and hop off as long as you have the cats they will hop back onto the cats and the frontline will kill them, i have only ever had to treat the house once when we first moved here , the previous owners had lost their dog about 6months before we moved in so we were left a nice legacy lol, when the concil man came he said only to treat the edges and along the front of the furniture as they dont live in the middle of the carpets only round the edges , keep up to date with your frontline and you will be fine you can buy frontline spot on online i find the spot on so simple to use a quick squirt on the back of the neck and they are none the wiser