Compost

Hello everyone.  I'm in phase 1 of designing my front garden and hope to plant it in the autumn,  nature's planting time. We're on a new development and the garden was planted by the builder /the landscape gardener he uses, in September 2014. Obviously 'new' topsoil ( I use that term loosely) was added. I've removed some fairly large shrubs which are neither suitable nor planted in the right place. The soil is like dust - fuller's earth if you know what that looks like.  I haven't any home made compost,  modern  estates don't provide gardens which you can make it, and I don't think that our neighbours would appreciate me getting a trailer load of farm yard manure which is what I have used in a previous life. What kind of compost would you put on to make it a more realistic growing medium please? Also,  how much? Cost is not an issue and I intend planting some shrubs, a rose or two and then under plant with bulbs.