Hi Paul,
I'd suggest having a read of
Frequently Asked Questions For The New Brewer and get a couple of brews under your belt. The Coopers kit you have comes with all you need for your first brew. The two things I suggest you pay particular attention to are sanitation/cleanliness and temperature - if you can keep everything nice and clean and keep the fermentation temperature to less than 20oC you should end up with quite a drinkable brew.
You have a heap of crystal there. Maybe once you've done a couple of brews look at steeping a small amount of crystal malt and ading it to one of the kit brews - see
Using Crystal Malt. You could also look to add some hops to the kits for flavor and aroma.
Read anything you can get your hands on. On-line resources like AHB and How To Brew are great resources and there are plenty of books by the like of Jamil and Ray Daniels that are well worth a read. Also have a listen to Jamil's podcasts that are available on-line.
Hook up with someone in your local area who brews all-grain so you have a better understanding of the process - sort of like a picture saying a thousand words. Not sure if there is anyone in the Mansfield area, but if there is and they read this thread, they're more than likely to say hello.
You haven't mentioned what styles of beer you like, but I'd suggest a simple Pale Ale. For a 20L batch, maybe 3kg's of the Pilsner and Ale malts, 600g of Munich and 200g of the Crystal (you haven't mentioned what type of crystal it is - light, medium, dark). Throw in some hops for bittering, flavor and arome to 30-35IBU's.
Anyway, my two cents worth.
sap.