500 BC and the Swiss Alps would have been inaccurate to place the Visigoths. In 500 BC the Swiss Alps (and surrounding regions) were under the possession of the Celts. Later, the specific Celts (Gauls) of the region were called Helvetti.
The Visigoths are not noted until about AD 270 after the Romans abandoned Dacia, which was then taken over primarily by the Visigoths.
Now, the Visigoths did attack Rome in AD 410 but their stay in Italy was brief and they eventually made their way into Gaul and Spain.