Using the relay shield to control 250 VAC / 10 A

I currently looking at some relay shield which is specified for
Specification
Voltage: 7~12V
Current: 8~250mA
Switching Voltage: Max 35V
Switching Current : Max 2A
Frequency Response: -1~1dB
Switching Power: Max 70W
Relay Life: > 100000

I'm thinking about using an extra relay to control 250 VAC/20A load.
then I saw some relay boards that can take care of 250 VAC/5A like the following
http://www.robotmesh.com/relay-shield-for-arduino

which website should I look for the relay board according to my specification?
if I can only do this by using an extra relay, what relay should I look for? I been checking out radioshack and other sites, but I'm having a hard time finding one I want.
Thank you in advance guys!