Best known for such '60s heartbreak ballads as ''I'm Sorry'' and ''Break It to Me Gently,'' Brenda Lee previously returned to her country roots in the 1970s before taking disastrous disco and easy-listening side trips a decade later. Now, on her first album in six years, Brenda Lee, she proves that her powerful Georgia soprano can still blow a hurricane off its path. Better yet, with songs like ''Your One and Only,'' she's gone back to the kind of material that made her a legend. Her country-tinged ballads and gospel-edged R&B use full arrangements that manage to sound fresh even though they remind us of her heyday in pre-Beatles America. Now it can be told: The early '60s are back, y'all. And Brenda's got 'em.