How to get footage from a sony handy cam on to a PC (by 2 users)

I am trying to download footage(on tape) from my sony handycam DCR-HC47 on to my Dell PC.
I have imported the sony software but when I try to import footage the software says it can not find the device and sugests that it is not pluged in and to check the i link cable
I am using the usb cable but also have a fire wire cable however there does not appear to be a place to plug the fire wire in on my tower.
I did manage to view the footage in another program called roxy but when I tried to capture it there was a unknown capture error and the saved file was blank ever time I tried it.
I bought this computer last month so that I could edit video and I am not happy that there is no fire wire/i cable plug.
I have to show my film at the tate moden on the 24.11.07 so time is deffinately a factor.
I am prepared to buy an editing program but want to make sure I get the right set up.

looking forward to some answers please help a frustrated artist!!!