Google Sketchup

[brickie in oz]

Hi.
I am doing a sketchup drawing of the pizza oven I built, Im having a few issues with some of the elements, mainly the oven arched top.

Can anyone help out with sketchup, Id appreciate it if you could.
Ive attached a pic, and the skp file can be grabbed here.

Once Ive got a good copy of the file Ill upload it here to my BrikiWiki that I am in the process of putting together.

Thanks for any help.

Cheers, Allan