Nichola Whiffen, 40, recently living at Radnor Drive, Knighton, was handed a four–month jail sentence, suspended for 12 months, when she appeared before Telford Magistrates Court.
She was also ordered to complete 130 hours of unpaid work when she was sentenced on May 20.
A warrant for her arrest was issued last week after she failed to turn up to Llandrindodd Magistrates Court after failing to attend appointments with the probation service.
Whiffen was convicted by Telford Magistrates of stealing the money between September 8, 2018 and January 9, 2020.
Mr Smith, who lived near Clun, shot to fame in the 1970s as the author of fantastical horror books.
He died, aged 81, at Royal Shrewsbury Hospital on Christmas Eve 2020, after contracting the coronavirus.
His 1977 novel Bats Out Of Hell, about a contaminated bat which escaped from a laboratory and spread a plague over the Cannock Chase, enjoyed a resurgence in popularity when it was reprinted during the pandemic.
Originally from Hopwas, near Lichfield, Mr Smith was educated at St Chad’s Cathedral School in Lichfield, and Wrekin College in Wellington.
His 1976 novel Night of the Crabs propelled him to fame, allowing him to give up his job as a bank manager in Birmingham.
He published 124 books and 4,000 articles and short stories.
Mr Smith's daughter Tara Paulsson said, after initially being employed as a cleaner, Whiffen began helping manage his affairs on the internet.
She said the theft had caused her father great distress during his last months.
"This was a very traumatic situation for Dad, as he was suffering greatly from immobility and hip pain and was awaiting an operation that never happened, thanks to Covid," said Mrs Paulsson.
"He had great affection for, and trusted, Nikki, who worked for Dad both as a cleaner and as an assistant for internet/computer-based work."
Mrs Paulsson said the thefts had also put an end to a long-standing friendship between Mr Smith and Whiffen's father.
"The Smith family had been friends with Nikki's whole family for decades, so this was a huge betrayal on all levels," she said.
"The missing money also caused friction within the family, as we tried to understand what was happening.
"Poor Dad was in denial about what was going on and also very embarrassed, I think.
"My mum Jean, my three siblings and I are relieved that we managed to get a conviction, thanks to the dogged persistence of Wayne Strangwood and his team at West Mercia Police, although sadly the resolution came too late for Dad, who died before the case came to court."
Mrs Paulsson added that elderly people were often very dependent on people they employed to care for them.
"We don't want anyone else to go through this." she said.
"Sadly, elderly and vulnerable people need a lot of assistance with their online communications and finances, and in Dad's case, Nikki shamelessly and callously took advantage of that vulnerability."