Give the first seven posts of the Superguide a read (link in the sigline).
The problem you have is likely your router and not the internet speed. After all, 3Mbps is more than fine for video streaming and online gaming doesn't require much bandwidth. If you're having latency issues with your setup and a 25Mbps connection, the problem is most likely with your network configuration and equipment, not your ISPs throughput. This post of mine might be of value to you -
Ask Daley: cable modems and routers.
You can use a single directional aerial to power multiple televisions as you've asked, but every split will result in signal strength degradation. Tuck a masthead amp in line as close to the antenna as possible, and consider replacing the splitter with a newer one (check specs for signal loss).
TV Fool is also a valuable resource for antenna setups and equipment.
You only have to pay for Hulu if you use a Roku box (granted, there's a larger selection on content via Hulu Plus, but not much that makes the money worth it versus waiting a week or two). Consider a cheap Android or Linux based HTPC instead running XBMC so you can do free streaming video from multiple sites, including Hulu's free content.