1) Adjust temperature of water at boiler stat to be a bit warmer if you can
2) Adjust speed of circulating pump to pump water around system a little quicker if you can
3) Balance radiators - close off the lock shield (outlet) valves a bit on the warmer radiators. Maybe open them a bit on the colder ones.
http://www.miketheboilerman.com/balancing.htm
Peccavi
January 2009