Will I notice the differance?

I second the Sony unit. I havce an older 707ES, and it easily beat several high-end budget players (rotel CAL), and matched a $5000 EAD unit.

My first recommendation is get rid of the RL-11. I had one of these, and grew to hate it. It really kills resolution, and makes the music sound muffled. They were trying to emulate a tube sound, but blew it in a big way. I ended up with a Classe CP35, which you can pick up here for around $300 - $500. This was one of the best purchass I've ever made.
Your speakers are very revealing, and deserve high resolution electronics. Also, if not placed well, can have bass problems. I tried a pair in my house. They sounded good, but the bass was never right. They sounded great in the store, though. This could cause harshness.

I own the Rega Apollo, and it is by far the most beautiful sounding cdp I've ever owned (I've also had the Planet 2000, the Ah! Njoe Tjoeb 4000 with upsampler, etc.)
The next batch of Apollos won't be here until beginning of March. So, save your pennies!
The Apollo does not make older cd's sound horrible; conversely, I found it makes them sound terrific. Whereas I could hardly listen to them before with the Planet 2000, with the Apollo they "come to life" and make it very pleasant to listen to them. The Apollo does not highlight the weaknesses of the older cds, but rather is able to extract more information from those discs and make them sound closer to a new recording.
The Apollo uses 20 meg of memory and 32 bit processing. One can easily hear the improvement in technology over standard 24 bit systems. Try, if at all possible, to audition one.
You can see my initial review of the unit on Audio Assylum:

http://www.audioasylum.com/cgi/m.pl?forum=digital&n=113988&review=1

You should be able to do well now in your selection. There are used Panets and Jupiters coming along since the people are upgrading to the Apollo. If you can stretch your budget, I would say don't hesitate to go for the top - the Apollo. But, even a used Planet 2000 would be a nice improvement. I had NO IDEA what I was missing in the music until I compared the them.

Get a used Rega Planet 2000 in the $500 range and spend the rest on music or new interconnects to hook up your cd player. You'll be very happy.

Thanks guys for the responses.

OK peeps, I bought a Arcam CD73. To answer my own question, yes, I noticed a HUGE differance. I am happy now. Very happy!