Glenn Nelson, who was jailed for the murder of Nepalese woman Krishnamaya Mabo last June, has had his 'unduly lenient' jail sentence increased from 25 years to 30.
Top judges decided that his 25-year term did not properly reflect the sexual aspect of Mrs Mabo's brutal murder.
Nelson murdered Krishnamaya by strangling her to death, to silence her after he tried to rape the mum of three near her home in Arborfield last June.
He admitted murder and attempted rape and was jailed at Reading Crown Court in October.
Lady Justice Hallett said, "He killed her deliberately to prevent her testifying about the attempted rape. The acts that resulted in Mrs Mabo's death were accompanied by sexual activity, which must have increased her ordeal.
"The violence and sexual assault were inextricably interwoven."