Around 200 people attended the gathering in Tudor Square on Monday evening, exactly a week after her disappearance in Machynlleth.
The vigil was organised by mum of two, Nia Payne.
She said afterwards: "It was just an idea I had after being so affected by April's disappearance. I have two children of my own, a six-year-old girl, Eleri, and three-year-old boy, Coel, so it really hit home hard.
"It is also so close to home and talking to other parents, I felt we needed to do something. I set up a Facebook event page and it just took off from there."
Those attending on Monday lit candles and signed a book of thoughts for April's parents, then at 7.30, lanterns and balloons were released into the night sky.
Continued Nia: "It was quite touching to see them go up as a lot of towns and villages were doing the same at that time."
Rev. Robb Wainwright, team vicar at St. Mary's Church, prayed "Keep her safe."
And as the sky lanterns were released, he added: "Think of them as carrying our prayers heavenwards."
Nia and a close friend also made pink ribbons for which they asked people for a donation which could either be kept or tied to the church railings.
Added Nia: "We raised £200 and the donation box and book of thoughts are still open for more people to contribute.
"Lesley Fisher, of Tenby House Hotel, offered tea and coffee to everyone who attended. To Lesley and everyone who helped out and took part, I would like to say thank you so much. To come together as a community like that was something we should all be proud of."