Well, the three you've picked are pretty good. I would agree with bernabeu
that the Minolta 50mm f/1.7 would be a nice addition for not very much money. I love it for low light, protraits, and kids photos.
And as I said, the 100-300 and the 75-300 are available used for very reasonable prices. I have the Minolta 18-200 and am thinking of the 75-300 myself.