Compost!

Since you're ready to plant I wouldn't add much 'raw' compost.

And definately steer clear of peat.

Sprinkle some bonemeal or bulb food before you dig.

How high should the raised bed be to avoid the grass ?
I have 100 bricks sitting around..
Where the real bed is, I have no problem with grass.My problem is that I did not plan well and now have to move some Iris and Hyacinth...and something else ?
What is wire grass, anyway?

I used to grow irises in an area that had very little, and very impoverished soil. I made my raised beds by putting down a thick layer of lucerne hay (alfalfa to you?) and then covering it with a layer of about 6" of good quality soil, laced with super phosphate.
By the time the iris roots reached the lucerne it would have broken down and provided good nutrition. I found my irises did very well in those beds. The beds tend to compact down after a while, but the worm take the broken down hay into the soil layer underneath, doing the hard work for you.
You could include compost etc on top of the hay layer, and underneath the soil, but you definitely need a good depth of soil for the irises.
Cheers, Jan in Australia.