Hi Peter,
The first thing you need to analize is the size of your business. In this link you can find a comparison on small business solutions.
Compare Solutions | SME Business Management Software | SAP
In this link you can find all solutions organized by different criteria.
Both links have contact options that may guide you further.
There are also consultant companies that may asist you in the selection process. When we do this tipe of consulting we usually start by reviewing the proceses in your company, what they are now and what you expect them to be in the near future. With this info you can check which solution meets your needs.
regards
juanpa