Is this the one you are looking at?
http://www.ozscopes.com.au/reflector...tor-drive.html
If so, a couple of points. It has an equatorial mount which will make it next to useless for terrestrial viewing (it is designed to track objects as they move around the sky) also the image will be a mirror image (upside down and back to front again making terrestrial use difficult. My 130mm newt came with an erecting eyepiece for terrestrial use but it was next to useless, the Celestron may have one and may be better but I wouldn't count on it. I assume by better "lenses" you mean better "eyepieces". Yes you can upgrade to better quality eyepices as almost all scopes use standard barrell sizes (usually 1.25" or 2") in their scopes. Dew heaters for eyepieces are usually essential and the issue is not how cold it is, I use mine even in height of summer. If you go with a Newt scope you will not need one for the main mirror (usually). Having said you need one, I use a hair dryer for months before spending on a proper dew heater kit.
Hope this helps and welcom to IIS
Edit: just read the specs on the website and it mentions "erect image optics"which mens there is probably a barlow lense in the focuser. Not a big fan of this idea as it places more glass in the optical train, produces dimmer images and is something extra to get scratches and damage.
Malcolm