New bike vs. updating old one...

I've been seriously thinking of buying a road bike. I currently have a diamondback hybrid that I do my road riding and training riding on, and a rockhopper for my real riding.

My purpose for road riding is to train for a mtb enduro event. I also want to complete a century before my big race at the end of July, so looking to do the century at the end of June. So here's my question:

I have about $1000 earmarked for biking this summer. I will need $200 for entry fees, $100-200 for extra bladders and misc stuff for racing, and I need a bike carrier and either a road bike with the remaining $500-700. I know I can't get a great road bike for that amount, but I can get a Giant OCR compact bike from last year. Does it make more economical sense to spend money to update my hybrid and use that so I can get the bike rack or just get a road bike?

The reason I want a bike rack for the top of my car is that I have a Honda Accord and for a race I will need to pack a tent, sleeping bag, food, etc along with my bike and gear and I want the extra room. I've tried the racks that attach to your trunk and because my frame is so small it doesn't fit in those racks nice and it scratches my bike and car.

If I go the route of updating the Green Hornet, what would be the best bang for my buck, i.e., what components do I want to look at and what kind of $ can I expect to pay:
1. I want new shifters so it shifts the same as my mtb. Right now they shift the opposite way and it messes me up when I get on my mtb (this is my #1 need).

2. New brakes. These are old rotary (is that the right word?) brakes that aren't used anymore and they don't work real well.

3. I currently have 3 rings, I don't even know how many gears. When I shift into my hardest gear my chain usually slips off or grinds real bad. Are there better gears/ gear ratios out there? My terrain is mostly gently rolling hills to flat. Not many really steep hills around here.

4. Handle bars. I switched last year to a more upright position because I have no curve in my neck (still working on that). I do like the more upright position but it would be great to be able to rest my arms and ride flat but not in the drops on some of my straightaways.

I don't know if I missed anything here. I think (keep your fingers crossed) I may have resolved my saddle issue but I haven't ridden over 20 miles with it yet. I believe this is a steel frame bike but I don't know - how do I check material on the frame and fork?

TIA for your thoughts and advise.

Without seeing the bike and looking up prices it's hard to say, but my best guestimate is you're looking at about $150 for all that. Honestly, I don't think the bike is worth it.

Can you get an extra wheelset and put some slicks on? That would be about the same price, and you get the benefit of being on the Mt. bike. That's what they showed the pros doing in off road to athens.