My name is Herbey or Herb for short.
You can buy chalk at a sporting goods specialty store or ordering it online. If your gym has a no chalk policy that is another story. Grip has generally been my limiting factor also. However, the first time I used chalk I went from 315 to 405. You can also try lifting straps.
If all else fails do deadlift lockouts for time ~30 seconds. Set the pins super high. You should lift the bar no more than 2 inches. Remember this is to strengthen your grip. Another idea is to do towel or rope pull-ups.