If you knew anyone who had a Vaio, I might suggest trying out an alternate adapter. The piece-o-junk craptop I used to use had the same battery/charger problem, but I ended up buying an offbrand adapter for it that eliminated the need for jiggling the cord. It sounds like the adapter's wiring was just messed up.

The new laptop would be nice, but the adapter thing would be a cheaper solution if you're willing to try it.