Importing or discovering devices

Hi

We manage a large network of about 1600 Cisco routers and switches. I have been evaluating Device Expert and i would like to know how i can import or discover 1600 devices. Ive looked at the help for the import option but unfortunately we do not have the details of the IOS version and model number of all our devices. We basically just have a hosts file with the hostname and IP address of 1600 devices. This is why we are looking at Device Expert so that we can keep an inventory of our devices. I tried doing the import using a comma seperated file with just the hostname and IP address but this didnt work. Would it be possible to add an option in the discover screen to discover from a list of IP addresses and hostnames? It is possible in the discover to enter a single IP address or a range but not a list.

Thanks

Mark