Does 'new' house mean newly built, or merely new to you? If the former, your garden site may be mostly builder's sand with a little landscaping soil over the top. If that is the case, you can try to amend it by bringing in stuff, or if your lot is big and you don't have shade issues from tall trees or neighboring buildings perhaps move the site to the margins where the native soil layers might still be intact (this presuming the native soil is at least moderately good).

Generic advice: Avoid any slope if at all possible. Don't buy any bulk stuff from nurseries or landscape suppliers that is called 'topsoil'. That is typically leaf-compost mixed with sand. The exception would be if you have very heavy clayey soil, so something like that would be a benefit. Generally you will be better off with barn manure, composted preferably, or fresh if you've got time. Buy hay or straw whenever possible to let compost in piles and keep thickly strewn over the plot whenever it's not planted or as mulch when it is. After a few years that should be all the input that you need.