the claybar ought to help with the roughness. you can buy a decent one from shops like autobacs; remember to use plenty of water when applying the claybar though!
waxing will help with the "dry" appearance of your paintwork. plenty of good and popular waxes, do a search of the forum and take your pick.
in the future, as a preventive measure, you may want to consider investing in a good, well fitting car cover and/or applying a few extra layers of synthetic wax(may not shine as well as carnauba, but it'll last and hence protect for a longer time) if you know its gonna be exposed to the elements for an extended period.
alternatively, if you choose to go the professional route, you can check out my thread in the New Products/Services folder found here:
http://bmw-sg.com/forums/showthread....2758#post52758
cheers