A few biographical details I've managed to dig up about Rossella Bergamonti:
It looks as if her real name was actually Rosetta Bergamonti and she is from Gussola, a comune in the Province of Cremona in the Italian region Lombardy. In 1962 she participated in the Miss Italia beauty pageant and although she didn't win, she finished in third place, earning the title of Miss Sorriso (i.e. Miss Smiles).
Here she is on the left together with Raffaella De Carolis (Miss Italia 1962) and Maria Lina Carreri (who came in second place and was crowned Miss Cinema).
Picture taken from here
And here she is on the right
From the La Stampa newspaper 3 September 1962
On 2 September 1962,
La Stampa also featured an article where a small presentation is given of the participants in the Miss Italia pageant. About Rossella it says that she is 20 years old (meaning she must have been born in 1942) and that she is 172 cm tall
And here the little text about Rossella in
La Stampa 3 September 1962, mentioning that she is from Gussola and that she came in third place
Her first known film roles are from four years after she participated in Miss Italia, but I think it's quite probable that she played some uncredited roles during the years in between, so we should be on the look-out for that.