Are there any excercises that will improve my strumming as that is the weakest part of me playing a guitar. My down strokes are ok but the upstrokes are retarded.
Just practice is the long and short of it. My upstrokes used to sound like an orchestra of dying cats, but it will work itself out in the end.
Hey Meg.
Proud of you.
I'd recommend playing scales (G Major or just any old Pentatonic pattern), and play every note upstroke. Start over and play every note downstroke, and on the last run, alternate.
--"Hey, don't worry; don't be afraid, ever, because this is just a ride."--
i can pick up and down fine i.e. alternatem, its just strumming chords up thats the problem
You can either create your own strumming patterns to practice with, for example:
Downstroke, Downstroke, Downstroke, Upstroke, Downstroke, Upstroke.

Or you can take a handful of songs with relatively simple chords (so as to focus on the strumming and not the chords themselves) and go through their strumming patterns to tightening up your own. For some off the top of my head:

Bob Dylan - Knocking on Heaven's Door
Oasis - Wonderwall
The View - Same Jeans
The Libertines - Music When The Lights Go Out
Staind - Everything Changes

but really any song with chord strumming, look it up on YouTube, listen to the patterns and try to emulate them as best as possible.