your 18-55 would be a better lens as compared to 18-70 or even the 18-105 although the later do provide the longer range which might come in handy but I would rather you invest in maybe a 18-200 all rounder.
Actually your 18-55 is a pretty darn good lens. Only thing is the construction feels light and 'cheap'. Optically it performs well though. "Punching above its weight" is a phrase that comes to mind.
Try posting some photos taken with your 18-55, and perhaps we can suggest any additional purchases you might need.
1 item to consider is a Nikon speedlight (sb-400 or sb-600). It really helps when taking photos indoors (eg. restaurant)
You can consider the 55-200 if you want a budget telephoto lens.
If longer range is your main concern, then changing to 18-70 hardly makes for an improvement. The 18-70 is more solidly-built, that's for sure.
In this case the 18-135 seems like a good choice. It seems to be poorly-regarded in general, but I find no real problems with mine... Maybe I'm biased. Definitely I'm not pro enough to spot the difference!
Beware that zooming in to such an extent will flatten the perspective (if you're taking scenery). That mountain in the distance won't look so far anymore. Also, long zoom introduces camera shake.