Police are appealing for witnesses to the incident, which happened at about 7.30pm.
The collision happened between a grey Volkswagen Caddy van and a white Vauxhall Combo van, with the lady being a passenger in the Volkswagen van.
She was taken to Royal Berkshire Hospital with serious injuries, which she later died from on Sunday, January 5.
Any witnesses to the incident should contact PC Joy Jarvis of the Road Death Investigation Team on 101.
Alternatively, call Crimestoppers anonymously on 0800 555111.