What kind of power connector do Sony VAIO laptops use

There's generally only two important variables in spade connectors:

1. Blade (not socket) width (the thickness may vary as well, but it should be prescribed by whatever the width is),
2. and if it's on a wire (versus a board), wire gauge it accepts.

Measure the blade width (I've only ever seen them specified in inch sizes, 0.187, 0.250...), and see if there's a good match on some parts catalogs (here's the Digi-Key category). After that, pick the one that fits a wire gauge that will safely carry your current.

It's a ITT Cannon MiniRF test connector (Part No. 120220-0180) or Hirose MS-156C Receptacle. These components provide a straight-through connection until a test probe is inserted in the hole at the top. Which end of the connection the test probe is connected to depends on which way around the connector is soldered onto the PCB, so that would determine whether it would be possible to connect an external antenna here. However these are not latching connectors (unlike the u.Fl mentioned above) so not ideal for a permanent connection. You might be able to solder on a u.Fl connector in its place though.