This Wireless Routers Extend Range Antenna for Linksys DLink works for the purpose. If you want to buy an effective antenna to increase coverage of your Wi-Fi signals then you can buy this Omini directional antenna that comes at an affordable price from Amazon.
Of course, it will deliver the best performance on your LAN or it may improve the signal quality of your present antenna. Please make sure that it is a single antenna, not a pair of antennas. You can easily get rid of your puny original router antennas with the help of this multi-directional antenna that covers a long distance.
You can easily walk through your home, outer areas of your home with a laptop and you will notice that signal doesn’t drop even at one acre of distance.