Hi all I have a Addon 150Mbps WiFi Wireless N PCI Express Adapter Card 802.11n NWP200E and I was wondering about adding a larger Antenna for the PCI card not the router as the router does not have an external changeable Antenna.
I wouldn't spend too much on a new antenna, it's not going to make too much of a difference. A better antenna than the one already on the adapter will probably cost more than the adapter itself so you may be better off getting a new adapter.
I would suggest a usb adapter that you could place on top of your desk (they usually come with an extension cable/base). The PCI models tend to get worse signal due to the fact that they are usually placed behind the PC case under a desk, where the actual PC causes the most interference.