If you have the money to spend then use it. But be aware when I was paying for AdWord, people were signing up 3 -4x's a day as "Referred by Google" and would leave immediately after signing up. When I stopped the costly ads, no more referred by Google. I'm not that familiar with Yahoo, but I don't use them for marketing, but they crawl my site frequently. I've also received many user from them.

Do a keyword comparison, and see if yours is matching the competition.

You might post this question under marketing also.

BTW, the business name alone will draw lots of visitors out of mere curiosity. I'm sure you'll get lots of "word-of-mouth" visitors.