Hello flower, you should check out http://www.sitbackandrelax.com.au and if you go up pretty close to the top on the right hand side, you can search for any Office Furniture, Office Chairs. It is very complete and helpful.
Yes of course there are lots of online furniture stores available. What all you need to do is first google about the right online furniture shop. Here, I would like to inform about my own experience. I was looking for separate furniture for my pets, and I had no idea, but thanks to this post that given me through knowledge about the cat furniture. http://culturedcat.com/2014/01/is-cat-furniture-a-fad/
I order furniture only here - fitted furniture & bedrooms I like their prices, quality and service and advise it to all my friends. Hope it will also help someone here!