If you are just doing this for fun.. then there is really no reason to change your camera. Full frame is the best, you will never want to go back to crop sensor after that. You don't have any lenses that are worth it to stick with canon. Now if you had some good professional fixed aperture lenses that ran you $1000+ each then I'd say stick with canon.. though you could easily sell your stuff and just get used nikon gear for around the same price. I personally prefer Nikons over Canon because of the menu system and how I can easily change my important settings like shutter, aperture, iso and focal point without having to look at a menu or take my eye off the view finder. Those to me need to be a quick change when shooting sports or little kids.
Being a beginner or novice or pro is a matter of your quality of work... not years experience.
I've seen way too many people go out and spend around $2000 on camera stuff and then switch it to Auto and call themselves a photographer. Its even worse when I see them take a shot and the flash pops up on camera.
If you want to stick to canon because you like them.. .then you could get a full frame Canon 5D mark 2 for around 2k used. But seeing as it looks like your more of a hobbyist.. I'd go with an EOS t3i, I think the 70D is the next level up not sure.
Best thing y ou can do is invest in good lenses. Doing landscapes you should get yourself a wide algne lens... like a 10mm
