You're wise to think about outgrowing your machine - I was also a new sewer and the first machine I bought was a Janome, which I quickly outgrew. As my skills improved I wanted to do more and more. I also wanted needle up/down, auto thread cutter etc and bought a another Janome (a TXL 607 which I don't think you guys have) which I loved from the minute I took it out the box.
However, at a quilt show I saw a demo of a Pfaff, which has a built-in walking foot and I fell in love with it. I now wouldn't buy another machine without this feature.
I suggest you make list of all the features you feel are important to you now or think you may want, and look at a few machines with those features.