There are some steps you can take yourself at little or no cost apart from your time.
The first is have a look at competitors sites. Do what you think they do well.
The second is design a clean, easy to view simple web site.
The third is put information on it that your customers may find helpful: safety tips, prices, etc. the sort of stuff that might keep them engaged for a minute or two reading.
Make sure you use words that people would search for. (But dont over use them)
Fourth is register you site on Googe maps.
Fifth: put google analytics on your site so you can check who is visiting.
Sixth: register in forums that your customers might read. Provide articles with you company web site and terms you expect people to search for next to that link: e.g.
http://www.ava.co.uk software for flexible staff management and temp staffing agencies
Do this on a regular basis.
Of course all this takes time. Cost out your time. May be an SEO company can do it more effectively and ultimately at lower cost. There ia an article on DIY Seo on our site.
http://www.ava.co.uk/support/faq/simple-diy-search-engine-optimisation-for-everyone.aspx with some hints.
Hope this helps, if it does click thanks