Cron jobs to import categories and products

Hi there i am a OpenCart 1.4.8b user i wonder if there's some way to import categories and products/products details using cron jobs or some automated script
Till now i've used import/export tool to import all the things in my shop but the problem is that i must do it manually every days because my supplier stock changes everydays, they add; new products, change prices, add quantities.
My supplier offer me a customized csv or xls file which is updated all nights around 5:00 am so what i have to do all mornigns is to download the file from their server, save it on my computer then with import-export tool upload it.
Would be great if i find a way to automate this process, the database file (xsl or csv) is online i must think about something that download it all nights and update the mysql with new items-prices-cats etc.
Any imput please?

What would be if i modify the import/export tool like this:
instead to lead the file from Local give a remote path then with cron run the .php script?
I am really lost.

I'm facing the same problem. Did you find any solution to this problem?
Your support will be highly appreciated.

Thanks