To Firewire Or Not To Firewire

Question

First post here ~
I have a 15" Powerbook G4, 1 GHz, 1 GB SDRAM, 60MB Hard Drive that I bought in, ahem, 2003, but right now do not have the moolah to upgrade. I have FCP 5.0.1 installed and a Lacie 250 GB External FW Drive.
Since my computer only has one FW 400 port, I currently have a FW hub plugged into the computer, and into the hub I have a Sony DSR-20 deck (which I may need to give back and borrow a DSR-11), and my Lacie.
I have about 90 hours of 24p/24padv footage that I plan to log and capture and MAYBE create a trailer if neither I nor my computer will crash in the process. In order to do this, I will obviously have to get additional storage, with the note that I plan to capture selects and not ALL of the footage. I think I need two 500 GB drives, but I'm not sure that is enough to create a backup of all my media files. I know that I can also backup the project files and deal with batch capturing the media again should I need to.
I have read about Firewire vs. SATA, internal vs. external, and am looking for a little advice.
Also of note, I do not plan to do complex editing or create lots of sequences, etc. The reason for having the external FW drive is that I want to be able to log,capture, and organize my footage and then deliver all that to the editor.
Two questions (after extensive research):
1. Apparently it is not a good idea for me to have both the deck and the FW drive on the same bus. Considering that I need to get additional drives, I'm trying to avoid a problem. Is it possible on my computer to get another internal FW card/bus/upgrade to 800 or even a second 400 FW? Am I right that this will cost about $100?
2. Is there another solution to storage of the media files? I don't think my laptop can handle it all on an internal drive, even if I can boost it up past 60 GB, but that's why I'm here asking!
Any advice or suggestions are very, very appreciated.
15" Powerbook G4 Mac OS X (10.4.8) 1 GHz, 1 GB SDRAM, 60 GB HD
15" Powerbook G4 Mac OS X (10.4.8) 1 GHz, 1 GB SDRAM, 60 GB HD
15" Powerbook G4   Mac OS X (10.4.8)   1 GHz, 1 GB SDRAM, 60 GB HD

Answer 1

thanks for that advice - including the "go have dinner" part!
Don't want to stretch the Shakespeare thing too much, but here's the rub:
I got FCP when I was working on a project for NYU, and was able to purchase the whole suite at the educational discount of $399. As such I don't think I'm eligible for upgrades, alas.
Since I am not an editor and am not planning to do a lot of fancy stuff, just log, capture, organize, I thought saving the $400 was worth it ~ although I'm sure to revisit that decision. I have shot most of the film (not my first), am still raising money, producing, etc. There are good editors out there who know their stuff, and it's just too much for me to try to do it all alone.
I'll go to the Apple Store later today to inquire about the FW card.
thanks again, and I welcome any other input!
15" Powerbook G4 Mac OS X (10.4.8) 1 GHz, 1 GB SDRAM, 60 GB HD
15" Powerbook G4 Mac OS X (10.4.8) 1 GHz, 1 GB SDRAM, 60 GB HD
15" Powerbook G4 Mac OS X (10.4.8) 1 GHz, 1 GB SDRAM, 60 GB HD