Definitely a relational DB needed.
I must confess I have to never heard of "filemaker" - it may be good but if in doubt then go with Access.
It's "plug-inable" to many things, has pretty much universal ODBC support ...and at the end of the day we're all Uncle Bill's bitches.
(in English - everyone uses Access, everyone supports Access, everyone can link to Access).
If you can come up with a list of data that is needed then I'd be quite happy to knock up a decent database for you with the tables mentioned.
I must confess to being a bit "in the dark" regarding query/access rights to an Access DB as I don't use it for "real" applications but I guess it must handle things OK.
To come up with the tables/indexes you need to come up with a list of everything you want to keep, and how they relate (e.g. one customer has multiple orders. one customer has a single address, one order applies to one/multiple items, etc).
Usually around on the weekends, so PM me or post if you want me to do some digging for you - I know a bit an can probably find out the rest.