Broadcasting video and re-streaming

Have two cameras connected to computer via firewire.

Used USTREAM and their software to broadcast video using those two cameras.

Now need a replacement for that.

Still two cameras (for now), but now need a server for storing videos on hard drive and re-broadcasting with different quality.

Computer with cameras connected to it will broadcast video.
Server in data center will re-broadcast videos in low, medium and 1/1 quality.

I need an advice what software can be used for streaming from computer. Also need somewhat recommended server hardware specs. And last but not least, a software to re-stream video as well as record it to hard drive.

Thanks