As far as advertising, I recommend sites like Craigslist. It is free and allot of people read it. Put it in the cars for sale by dealerships section. You will have to repost it frequently, due to other salespeople flagging it.

Also, you indicated that you are just a regular salesman. If you think that way then you will starve. The difference between a salesman and closer are light years apart.

Work on becoming a closer and not a salesman. A closer makes a $100K a year and a salesman make $30K. Which one do you want to be?

Do ever fear a customer getting up and walking away. Be polite, professional, bold and don’t hesitate to call bullshit when the customer is dishing it out.

If they tell you they can get it for $3K less down the street, then the question that should be politely asked is, "Wow, with such a great deal, why are you hear?" They are their because that deal does not exist.

Closers call BS and nail people to the wall. Great movies on sales are "Suckers"; great for the car business and "Glen Gary, Glen Ross". The Alec Baldwin scene in particular. Both can be found at your local Blockbuster.

You have to have brass balls to close people. You have to be the mentally toughest person at the table. You also can’t close them all. You cannot overcome ignorance, stupidity or poverty on behalf of the buyers.
References :

http://www.freecrm.com/idev/idevaffiliate.php?id=618

Here is the company talk for it:

What is Free CRM?
Free CRM is a web based software solution for customer
relationship management and sales force automation. Free CRM is great
for contact and lead tracking, sales and contact management, sales
pipeline management and forecasting, customer service and business management.

What can I do with Free CRM?
Our Free CRM software and sales team automation tools speed sales and
customer service with real-world features that make your jobs easier. With
integrated email campaigns, call automation and tracking and group
calendaring, our Free CRM is smart groupware.

Good luck!
References :
http://www.freecrm.com/idev/idevaffiliate.php?id=618

You are probably looking for Customer Relationship Manager tool (CRM)

There are thousands of them out there, but I am assuming you want to keep this information for your eyes only. If that is the case then you need your own hosted web service with a built in CRM tool to do this.
An alternative is salesforce who seem to lead the way in this.
References :
http://www.sales-lead-experts.com/guide/guide-leads-tracking.cfm
http://www.salesforce.com/crm/sales-force-automation/sales-tools/

If you want employees to sell, you need to ensure that a large part of their compensation is tied to their sales. So give them a small base salary and a large commission portion; that will make them try to sell more.

You can also make use of non financial incentives – such as recognizing an employee who has made a good sale, or has taken an account away from a competitor – and give them recognition before their peers. Call a general company meeting and acknowledge the employee, then give him/her a coveted parking space, or a small gift card, whatever. You will be pleasantly surprised how effective such non-monetary incentives can be. People always love being recognized before their colleagues – use that to your advantage and benefit. It’s a win-win situation for everyone.
References :

Then do your job, SELL ! 99 no’s for every yes is part of the game.

You weren’t hired to sell cars to people coming to the lot intending to buy a car. They hire way more salesman than they need for that.

Your job is to beat the bushes and find customers and bring them to your lot and sell them.

Those other guys that work there ? They are your competition !

New salesman are pressured to sell cars to friends & family and after those leads run out, many salesman cant sell enough cars and are let go.

No dealer is going to pay you a wage after a month if you cant make more than that in commissions.
References :