What software should I use for tracking my stores' inventories?

I’ve been asked by my work (a small chain of take-away stores) to put together a database that does the following things:

1: Contains a catalogue of all the different types of equipment and assets that are available to each store.
2: Keeps track of which equipment and assets each store currently has in possession.
3: Allow each store to browse the catalogue, choose items they wish to order and automatically generate the purchase order forms required for the different suppliers each asset is sourced from.

I was originally going to design the database in FileMaker Pro, however some of the features I need such as automatically generating the purchase order forms is proving fairly difficult, and I am worried that I won’t be able to finish by my deadline, or that it won’t be able to be maintained once I leave. (I am only employed temporarily for this one project).

Does anyone know of some proprietary software that would help me with this project?
I’ve just downloaded inFlow to test out, has anyone had experience with this?

Thanks for your help in advance!