Ms Williams was speaking at the Lib Dem conference in Glasgow where the party leader Nick Clegg made a pledge about giving home rule to Wales.
"The Scottish referendum gives us an opportunity to rebuild and renew the union and to do that, we have to have more powers coming to Wales," she said.
The AM also ruled out standing as a candidate in the 2015 general election.
In a speech on Saturday night, Mr Clegg said under his party there would be more devolved powers following those pledged to Scotland.
"And what is right for Scotland is every bit as right for Wales. Under our watch Welsh home rule must become a reality," he said.
Speaking to BBC Sunday Politics Wales, the AM for Brecon and Radnorshire added: "I think we can do that now in the opportunity that has arisen out of the Scottish referendum - more powers for Wales, more powers to be able to do the things that are right for our nation."
Ms Williams also defended her party's decision to go into a coalition government with the Conservatives following the 2010 general election.
"Taking the decision to go into coalition wasn't an easy one but it was the right thing to do for the country," she said.
Welsh Liberal Democrat leader Kirsty Williams says Wales must have a greater say over its own destiny.