Hey Debsam,
I have the Hohner Corona II in G/C/F which seems pretty popular in Texas style musics. I agree with TomBR (why not?) about looking for a more standard scale ability on the diatonic. So, back to your question, though, I think the Hohner Corona II is a very nice three row button diatonic accordion, you can get the German version, or a cheaper Chinese version, depending on how much you want to spend. I can't say which is the better value as I have not tried the Chinese version. And being that you are in Texas there are probably lots of used ones around if you just want to try it out. I think that the real Texas professionals go with an Italian model after a while, like a Gabbanelli.
So, yeah, based on your playing, if you are looking for the diatonic experience, the Hohners are good, you can get them in the 2 row also. I also have a Della Noce 1.5 row for the Italian music, which I love too, the layout is a little different from the Hohner, more set up for Italian music than general tex- mex folk, etc.
The real question most of us are dying to know though is more about professional Greek accordion music in Texas....so, if you could enlighten us if you so desire....thank you and good luck, Tom