Let's get something straight here...
There is no such thing as a DV port or cable or whatever. There is USB and Firewire. As it turns out, both USB and Firewire each have two different kinds of termination (plugs at the end). USB has a flat-wide termination or a square-box looking termination. Firewiire also has two termination choices: a small one and a larger one.
Now, if you already have a Firewire port in you PC, then all you need is the right cable -- a Firewire cable with one termination that will fit in the camera, and another termination (at the other end) that will fit into your computer Firewire port. Without question, Firewire is preferred for DV. It is probably slightly faster (although that is debateable despite what everyone usually spouts off about FW being faster than USB), and it is the only way to be able to print-to-tape I believe (won't work on USB). However, depending on your computer (RAM, HD, speed, etc.), USB2 can transfer DV no problem without dropped frames.
So, chances are all you need is a new Firewire cable with the right ends on it. Otherwise, you probably ought to be able to get USB2 working too, but that might require a driver that you haven't installed possibly?