Harry's parents, Charlotte Charles and Tim Dunn, have vowed to fly to Washington and take legal action against Ms Sacoolas.
New signs have been installed near RAF Croughton in Northamptonshire, reminding drivers to stay on the left.
In a post on the GoFundMe page, Dunn's family said: "We are overwhelmed by the generosity and the support from all of you and want to say thank you again personally from the bottom of our hearts".
"We will be meeting with various news channels to spread our campaign with all of America and ultimately hope that the American government see that it is right to send Anne Sacoolas back to the United Kingdom to face our justice system".
It is not clear when exactly Sacoolas departed the U.K., but police told NBC News that they were advised September 16 that she had already left the country.Sky News, which is owned by NBC News' parent company Comcast, reported that Jonathan Sacoolas was not on the published list of accredited diplomats in the U.K. The British Foreign Office disputed the claim and said that he was an accredited diplomat in the eyes of the British government and his wife was entitled to diplomatic immunity. "The note, caught on camera by a Washington Post photographer, told Trump: "(If raised) Note, as Secretary Pompeo [the U.S. secretary of state, Mike Pompeo] told Raab [the UK foreign secretary, Dominic Raab], that the spouse of the USA government employee will not return to the United Kingdom".
On Friday, the Prime Minister said America is "absolutely ruthless" in its safeguarding of Mrs Sacoolas following the decision to grant her diplomatic immunity.
A statement released on behalf of the family said: 'As if losing Harry was not enough, they now find themselves having to expend enormous time and energy, which they can ill afford, generating sufficient publicity to garner public support to persuade the USA government to help achieve closure and return the driver Mrs Sacoolas to England to face the consequences of her actions.
"I must say, I don't think it was appropriate for that provision to be used in this case". "I made that point to the president and he is sympathetic", he said.
Raab met Dunn's mother, Charlotte Charles, and his father, Tim Dunn, on Wednesday afternoon after speaking with the U.S. ambassador Woody Johnson.
Speaking of taking their campaign to the US, Harry's family said in a statement that they "continue to live in a nightmare" and have so far been unable to grieve after his death.