Welcome to the Q&A Forum

If there's room in the advertising budget, go for it. It's a quick way to get a high authority link and if your competitor's are listed, by getting listed too you remove that advantage, whether it's great or small.

See the SEMOZ directories list to see how the Yahoo directory stacks up against the others. (http://www.seomoz.org/directories)

This is something I read back in early December, though I have no hard data on this... so consider it hearsay for now.

Google are apparently trying to make the places system more robust by introducing a real places support team and are rolling it out slowly. These "technical reps" started in Kansas City and recently answered a few questions including yours.

_Google is going to begin advocating to businesses that they set up computers/workstations where clients can post live reviews in their place of business.  There is no penalty for "same IP address" moving forward, assuming a "reasonable number".  The technical Places sales rep indicated 10 or less per would be acceptable, and more if the business type warranted it.  _

There algorithm will flag more than 10 a day.

You're not blocked by Google, your site is indexed in G no probs. You do need to cultivate some backlinks to earn pagerank. The site's fairly new, looks like the domain was purchased only a few months ago. Pagerank takes time, and consider that the pagerank number in the toolbar is updated only 1-4 times a year.

Concentrate on building your mozrank with quality links. The easiest way to get started would be some of the directories with better reputations as seen here http://www.seomoz.org/directories , fill out your profile on aboutus.org/davincidrivers.com and request a dofollow link, and work on getting links from relevant sources.