Perhaps, you should split the jobs up seperately, I', also doing this at the moment, but opted for as much diy as possible.
Fence - I recently got a 4 bar wooden fence and rail supplied and fitted for 14 euro a metre
Trelis - I done this myself, By a cordless screw driver, a bag of screw. get a load of 2X1 (or smaller) lengths of timber from a saw mill and make it yourself, its idiot proof (i.e. I could do it)
Garden - This is the tricky part. If you are not in a position to do it yourself, check out your local trader/local paper and there should be loads of dudes listed.
Consider doing it youself - Lanscaping is a personal choice and something you will probaly build on over the years to add your own mark. Our neighbour got a professional landscaper in last year and had the garden done inside a week, but in my opionion is looks staged and like the grounds of a hotel.
Cheers
B