You should be able to purchase a "bluetooth adapter" for the tablet. They attach via USB. Just like a Wi-Fi adapter for a computer that doesn't have Wi-Fi.
This would then allow you to use it that way. There are tons of them out there. A quick search will find you what you want. Just make sure you only get one that will work with "your" tablet.
They are also usually pretty cheap. Many can be found for under $20.