Integration alternatives

I'm doing some fact finding in order to get insight into how we can integrate our software with SAP. Essentially, we have a supply chain application that needs to read typical data like items, locations, SKUs, purchase orders, sales, demand forecasts, etc, from the customer system (i.e. SAP), process the data, and bring the output back into SAP. There seems to be quite a few ways to do this. Our software is a typical batch process -- e.g. we need large volumes of data every weekend, crunch numbers for a few hours, and then produce a report. I would be grateful for any comments and pointers on how we can go about doing this, what the important factors are, and where I can educate myself on the alternatives that SAP offers.

Thanks,

-Kaare