Hi Lilith,
It is recommended that you find a web host that will store your file for you online, so that you may link to it from the screening room. If you do not have a web host, you can look into upgrading your IndieTalk membership to the Premiere Plus or Premiere Pro levels. These levels include some storage space at IndieTalk as part of the package. But, depending on the size of the movie you want to upload, you may need more space than these higher membership levels allow. If so, then you definitely need to look for a web host.
I run my website through a web host service that charges $29.94 every 6 months ($4.99/mo). If you want more details on that, send me a private message. You may also find movie sites that will host short movies for a fee. Try searching for movie hosting.
Hope that helps.