I have a router that can be used as a range extender, but it needs to be plugged into the modem no matter what I use it for. Does your Jetpack have an Ethernet plug? That's a good way to figure out if you could even plug in an extender. Next would be figuring out if it's compatible.
With few exceptions, modern Range Extenders or Wi-Fi Extenders or Wireless Repeaters can be used on most any Wi-Fi network. I have no idea what model works best, so you might Google review sites. Click the link to Newegg.com and select Most Reviews in the Sort by: drop down. You can get an idea of how good the product is by the highest number of reviews with the highest rating. Wal-Mart has a number of Wi-Fi Extenders and an easy return policy if you don’t like it.