Digital BW, The Print

I am have a few newbie b&w printing questions, so I hope that there 
is someone with patience out there. 

Background. I am a hobbyist: whilst I like b&w photography, the only 
place you'll find one of my prints is on one of my walls. I've got a 
Canon 10D, and PE2, which was bundled with it. I have just acquired a 
silveroxide.com FP4 plug in filter for PE2. My printer is an HP 5550, 
which is not the best starting point, I suppose (I get the impression 
that HP printers are not considered serious contenders for b&w 
printing). I am told it shares the same engine as the hp7x50 range. 
It takes two carts at a time: either two colour or one colour and one 
black. Two colour carts produces acceptable prints up to 8x10. It was 
also cheap as chips. 

What I am finding when I print b&w images so far is this:
- using two colour carts produces unmistakably sepia prints. 
- using only the black cart produces a dirty, slightly brown tinted 
printed, which is highly grained (around ISO800), and moreover the 
transverse printing lines of the cart are visible. 
- using one colour and one black cart produces a print that looks 
blue & white. Interestingly, the local photoshops produce a similar 
looking print from b&w images. I haven't tried any of the more 
commercial print processors in London yet. 

My questions are
1 What is the best I can expect to get from my existing set up? I 
have seen references here to 4 and 6 tone black printing, but mostly 
in the context of Epson and Canon printers. I am guessing therefore 
that there is some hardware distinction that stops these inks being 
using in HP printers. Is that right? If not, any ideas on where I 
start looking for 4/6 tone inks that would be suitable, and how I 
would get them into the HP carts I have (by which I mean I guess that 
you can't just bung any old tone into any old part of a cart)?

2 I have tried (but I am thinking about) using profile prism to 
profile my printer. Is that a pie-in-the-sky idea for b&w? I assume 
you need access to a good quality scanner – anyone able to confirm?

3 If the limitations of my existing set up are unsurmountable, then 
from the things I've gleaned here, I guess I am looking at something 
like an Epson 2200. Is that the realistic "entry level" printer? I 
ask because if so, then assuming I can find a satisfactory bricks and 
mortar outlet that can/will produce a good print, my volumes probably 
cannot justify a 2200. 

Thanks for listening, sorry about any jargon gaffs, and thanks for 
any responses.

GB