You have two choices.
1. use the FireWire (IEEE 1394 is the same thing) port that Dell lists as being on the machine http://www.dell.com/us/en/dfh/notebooks/inspnnb_1525/pd.aspx?refid=inspnnb_1525&cs=22&s=dfh
FireWire devices can be daisychained, which means you plug one device into the port on your computer then the device will have 2 ports on it, one for connecting to the computer and another you can connect another device to and so on. So, you only need one FireWire port on your computer.
2. Purchase an Express Firewire card (not PCMCIA as Dell uses Express ports instead) such as this http://www.belkin.com/IWCatProductPage.process?Product_Id=277548 and plug it in!