welcome scubagirl,
http://www.andrewscom.com.au/site-section-10.htm
Andrews is probabley the cheapest of the good to great suppliers (in my opinion). He is based in sydney along with Bintel
https://www.bintelshop.com.au/welcome.htm.
http://www.andrewscom.com.au/images/.../70x700az2.jpg
are refracting and basically your cheapest $199, pretty easy to use.
http://www.andrewscom.com.au/images/...nian/gs580.jpg
are called "dob" based units, moderately easy to use $299, but you get to collect more light and see more with it.
Dobs are very popular. The girls will be tall enough to look thru the dob as the eyepiece is near the top.
For your 113mm reflecting
http://www.andrewscom.com.au/images/...ctor/gs280.jpg
$399, but i am guesing the girls may have to stand on something to look thru it.
I would go the 150mm on a dob base for $299 as you can always buy a mount later.
I notice you are from Victoria. There is a Star camp at ballarat with families and all staying there for friday 30th to 2nd nov. It would be well worth the day trip pop in, see all types of telescopes
Yorke are in the city in melbourne, but everyone seems to use the guys in sydney.
You will get great help from the guys and girls on this site.
Welcome