Hi. Just make a letter to the addressee indicating the purpose of the visit and that you will take care of the needs of the visitor preferably in company letter head. For direct relative usually affidavit of support from the embassy here is not needed but for assurance you may want to get one. Send her these letters, your PP, QID, employment certificate and RT tickets and she will be fine. That is provided your mom is not more than 60 years old. Good Luck.