By the sounds of this I don't really know if a second cat would be a good idea... Your already having trouble with the first and if it doesn't work out you have 2 cats to find homes for. Honestly your cat is acting like a CAT!! lol sorry to put it this way, it seems to me as if she's enjoying the attention right now being naughty.... If you ignore her it may help. I hope it ends up working out for you every cat is different not all cats are lap cats and maybe she's npt she just acted that way at first cuz she was in a shelter. Good luck anyways and really think before you get another cat.