Welcome to the Apple community.
I have to say with your download speeds as they are, you have done particularly well to download a movie in only three hours. Unfortunately, there is nothing you can do to improve matters unless of course, you are prepared to upgrade your Internet service.
1080p HD movies require a recommended speed of 8 Mbps, 720p HD movies require a recommended speed of 6 Mbps, while SD movies require a recommended speed of 2.5 Mbps.
Until you do upgrade your Internet service, you may wish to consider purchasing or renting from your computer. Make your selections in advance and download them to your computer, this will avoid problems with having to re-download content should you turn your Apple TV off or use it for something else whilst it is downloading.
I have the same problem! I have a 10 mb internet service. and I did the following:
1. i rented a movie and it was downloading at 1mb/s, paused it
2. start download the free yellow submarine book by the beatles and it downloads at 9.99 mb/s, I even pause this download and continue with the rental, and the rental downloads at 1 mb/s.
Fernando, I look forward to reading someone's answer ( who's smarter than me) to your movie download dilemma.
My download issue was caused by Time Warner's daily (3:00AM) updates to their componets. Occasionally, (1 in 500 according to one of thier technicians) a cable/internet modem is "disturbed" by this update.
So even though we were paying for 40 mgps download speeds with our internet service we were getting 484 kbps download speeds for weeks. Time Warner does not test thier equipment's speeds nightly, even though, I believe it is technically possible and practical with their existing equipment ( obviously a software change would be necessary).
By "resetting" the modem (ie. unplugging it from it's power source for 10 seconds) the "problem" was resolved.
I used Speedtest.net to "ping" Time Warner's server and then called (ie. Calmly but obviously furious) Time Warner with the results!
The moral of my story is: test the speed of your internet connection and contact your ISP to get the results for which you are paying! If my story helps you, go get 'em...and get a discount!
I look forward to reading about the underlying cause of your movie download speeds.