Mrs Yeats was not surprised at the high numbers in support.
"The people around us have seen the difference it's made for Grace.
"Even if they were kind of anti or sitting on the fence before, now they can see what it can do to ease suffering."
She said since beginning cannabis treatment in November, Grace was seeing all kinds of benefits.
"It's calmed her dystonia down a lot, she has more purposeful movement in her hands which has enabled her to communicate on her iPad and do her school work a lot better.
"Plus she can now talk, as of late February, and I do put that down to the cannabis."
Mrs Yeats was disappointed to hear Prime Minister John Key on the radio saying he was not a fan of decriminalising the drug.
"It's just like beating your head against a brick wall - they just seem so set in their attitude - it really just brings you to tears."
So far Grace's treatment has cost $8000, at $1100 a month.
The money to pay for the drug was raised through Givealittle, with Mrs Yeats saying "that money won't last forever".
She "desperately hopes" that when the fundraised money runs out there is a cheaper alternative to Sativex available to her daughter.
"It hurts handing that money over to the pharmacy when there are other things that we need as well. I mean it's a plant that I can grow in the garden."
Medical Cannabis Awareness New Zealand co-ordinator Shane LeBrun said the decriminalisation of the drug would benefit thousands of Kiwis.
"If they decriminalised it then a lot of people in chronic pain, like my wife [who suffered a spinal injury], would be able to have a bit at home without the fear of prosecution."
In a country of 4.5 million people, fewer than 40 were on Sativex, New Zealand's only legal cannabis-based drug. He said this was because many people were not even aware of its existence, with some doctors reluctant to prescribe it.
Wairarapa MP Alastair Scott said he would not advocate "smoking any drug that's going to do long-term damage".
But making cannabis available for medicinal use was "a no-brainer".
"If you've got a doctor who prescribes some sort of cannabis-based product, or morphine-based product, or a drug that would be dangerous in the hands of the general public but the doctor wants to prescribe it then I'm absolutely in favour of the doctor being able to prescribe it."