First off: Welcome.
What type of cables/clamps are in place now? Something like you might see in a car/truck or just a cable with an "eye" that's bolted to the battery?
I'm assuming the type in an auto based on not being able to tighten it any more.
Safety first: always unhook neg first then pos, and pos. first then neg when hooking back up.
Unhook your neg and trace it back to where is terminates (probably the engine block). Remove it. Now do the same with the positive (if you want to replace it). Take them to local auto parts store and match them if possible. ETA: You may have to get one that is a little longer, that would be fine. Shorter won't work.
