Entrepreneur needs quick FICO boost

I am a college student (22), who needs as much credit as possible for my business, which has been quite successful buying things and re-selling them on the internet. My FICO scores range from 581 (TU) to 682 (EX). In the past, I was able to use my mom's cards, but I now have a corporation and need to get corporate cards issued with me as the officer, if at all possible. The business, in the past, has needed revolving charges of as much as $25,000 per month, which were immediately paid off.

My problem is that in high school, I got 2 credit cards which I forgot to pay when I went off for summer vacation. These were my very first cards. They were both 2 months late, and both closed by the creditors. The balances were extremely low (maybe $40-100 on each card), but the credit damage was severe because I had no history. In addition, I was sued by the local library for unpaid fines, and they got a judgement (which I immediately paid). However, the judgement remained unpaid on my credit report for years. I found out they needed legal fees of $20, which I sent. Now, the judgement is recorded as paid this year (some paltry amount as well). One of the credit card companies from my high school cards went bankrupt, and I managed to get the notation removed from my reports by disputing it. I also have numerous inquiries, because I kept applying for cards in the hopes that I would get something. This has excerbated the problem, and I am now seen by the computer as someone who doesn't pay their bills and is desperate for credit.

Since the incident in 2000, I have always paid my bills on time, though I have been bad about maintaining consistent charges every month, and patterns have been erratic because of business activity (i.e. maxing out the cards, paying them off immediately, then no activity for months).

I have managed to get 2 credit cards, one with a $500 limit from Household Bank, and one with a $3,000 limit from Providian (built up from $1,000 over 3 years). I want to know how to get the limit more into the range of $20,000-$40,000 as quickly as possible. I realize this will take time, but I want to expedite the process.

I am an authorized user of my mother's card, which often have high balances (but they are always paid off in full). Even with the consistent payouts, this seems to hurt my score, as I am thought to be "overextended," (for my score, my balances are high, so banks are unlikely to extend more credit), but the charges aren't mine.

My questions are as follows:

1. Will taking out a CD loan improve my FICO scores?
2. If I take out a student loan and start paying it off immediately, will this help or hurt?
3. What else can I do to raise my score as quickly as possible, even if it costs money? It has taken years just to get $3,000. My corporation is listed in my credit report as my employer, which seems to have helped a little. On time-payments have gotten my limit tripled to $3,000 on my Providian card, but it is slow going.
4. The card on which I am an authorized user is old (1994). Is it better to keep it on my report, or get it taken off? Balances can be high, and my score plunges when this happens, then goes back up to normal when balances are low.

Any help would be much appreciated!

Manny