SEO and Google Adwords are vital to the growth and success of businesses in todays world. Choosing a professional seo company is extremely important, make sure you check their organic position before signing a contract as if they cannot rank their own website well, what makes you think they can do the same for your website.
If you have a limited budget, it is highly recommended you start with Google Adwords. SEO is powerful but it is more of a long term investment. Also remember, these two methods provide great means of obtaining targeted traffic, but its up to the landing page to convert the traffic into sales. Its highly recommended you create a professional landing page before running a Google Adword Campaign.