Canon Digital Slr Cameras Uk

Canon EOS 450D advice please.
Recently I bought the camera above comes with standard lens 55mm-18. I'm going on vacation in Canada, end of year and I would like some advice on what lens / accessories i may be necessary to enable me to take good photos (Rocky Mountains and we hope that some wildlife, etc..) I saw a lens on Amazon UK, which is a Canon EF 55-250mm f/4-5.6 IS IS S telephoto AF for a selection of digital SLR, this lens is good / sufficient? I do not want to spend a fortune on a goal, because I am an amateur! To what extent the distance of the lens zoom and always give clear images? (For example, if I saw an animal from 150 meters Zoom at the time)? I'm completely new to the DSLR world and so any advice would be appreciated. Thank you.
Well first few accessories. Youl want a parasol you do if your landscape photography, especially if the use of a lens down. This allows the brightness of Objective. You'll need a tripod for landscapes. Because landscapes reqirements using f-stop numbers high (F/16 of/22), this means that the hole size of the lens is smaller, allowing less light, this means, then, must use a shutter speed shutter slower to compensate, and if the hand can cause blurred images. last thing you want a remote release. It is a device external trigger that connects to one side of the camera, allowing the shot release button or the remote, not the camera, reducing blur. This is also good if you want a landscape picture of stars. Set your camera bulb mode, and hold the shutter button outside about 1min. That means no blur and a brilliant night photography. Im on the iPhone, so I gotta go, but I hoped that helped add me on my e-mail if you want more help larryrobinson_1@live.co.uk GD luck:)
Loading Film into a 35mm SLR Camera