You may want to keep your old machine - mainly so you realize how good the new one is. Basically any sewing machine you can buy these days is computerized. So what is the difference? Its in the myriad of features and accessories. Typically the better known brands will offer the sewing machines with the most features at the best price.
The best way to decide on your purchase is to compare different models in detail, and choose two or three that appeal to you - then go to a sewing center and test them out. If you buy from the sewing center many times they will offer free classes on how to use it, or sometimes in-house service. But many times the best deals can be found online. Its your choice where you buy, but I've listed a few computerized sewing machines here that offer lots of options for their price range. If you care to read you may just find one perfect for you.