Sony did not buy Vivitar.

Sony bought Konica Minolta camera division.

You can probably still find Konica Minolta DSLR cameras at many camera stores. New and Used.

The new Sony A100 is supposed to use all of the Minolta lenses.

They do not guarantee that it will use a Vivitar lens.

The only way to find that out, is to contact Vivitar.
They will need to have a full description of the lens.
(Model number, focal length rating in millimeters, and f-stop rating)