Need Studio Lighting Suggestions
I agree, get a hot-shoe flash first. If Sony sells a hot-shoe flash then buy it. If not then buy a compatible flash with a sync cable connector so you can use it off-camera as well as on-camera.
To learn what you can do with a hot-shoe flash on and off the camera study Lighting 101 and 102 on David Hobby's Strobist blog.
Don't get any of the hot-shoe flash accessories like Gary Fong sells - almost all hot-shoe flash accessories are a waste of money. Once you study Lighting 101 and 102 then you will have some idea of what kind of accessories will work well with a hot-shoe flash.
Once you understand fully what you can do with one or more hot-shoe flash units then you will be ready to consider buying studio strobes.
I would also recommend that you look over this web site which is a good guide to on-line tutorials and books on photography.