More cash needed I fear if you intend to take pictures for publication
Landscapes would require a wide angle, looking at minimum 250-300 quid for something like a Sigma 10-20 and upwards from there
You would also need something in the range of 17-55 or so for the everyday stuff, so about the same again for a Tamron 17-50
Could try using one lens for the lot, along the lines of an 18-200 but the quality would be compromised as the focal range became stretched.
Ideal would be the wide angle plus midrange lens I mentioned and then a 70-200 for the longer stuff
If I just wanted one lens my choice would be the canon 17-55 IS, superb picture quality,but its big bucks
There again may be worth it if you are getting cash back from the pictures
And don't forget a decent tripod too