That depends on a number of factors. What kind of business is it? Is it in a popular niche?
The most likely causes of traffic coming up shorter than you expect would be an unattractive site, a site that's difficult to navigate or doesn't function properly or a site that has too much "going on" and has a slow load speed.
May I see the page?
The best traffic comes from twitter,reddit,digg,stumbleupon and places like that. Do not buy traffic cause it would just be a waste of time and money.
You stated that you launched an on-line marketing campaign. What was the purpose of the campaign? Are you just building brand awareness or trying to get people to purchase (conversions)? You need to judge your traffic based on the purpose of the marketing.
If your purpose is to sell a product, than you don't care about the traffic. You need to know how many of the visitors actually purchase. If ten people visit and 2 purchase, you're campaign was on target and reached the people when they were ready to buy.
If you are just driving awareness, then you want more traffic. You should set up some way to get feedback from your visitors. Get them to sign up for a newsletter, download a brochure or something that shows you have their attention.
You might implement Google Analytics, if you haven't already. Not only will it tell you site visitors and unique visitors, it will tell you what page they were on when they exited. Having hundreds of people hit your site is worthless, if they don't navigate to other pages to view content. If your campaign was off target, you could be driving people with little or no interest in your product or service. That would result in great traffic, but no marketing success.
How is your on-line marketing campaign going? Please update us on your status.