If you have a look at:
They have a list of the Aikikai dojo in and around Brisbane and the Gold Coast.
Not sure about Toowoomba specifically, but the guys at Aikido Queensland might be able to help out...
Toowoomba is a little under 2 hours drive from Brisbane (about 130kms) so it is not too bad a distance travel-wise...
Warwick is another possibility, being about 1 hour 15 minutes from Toowoomba and 87kms.
Both dojos are run by good people and they are very friendly
Hope this helps.