My ASUS will give a signal about 50 yards, but that is it. And that is with extended antennas and a repeater. But like router, depends how many walls the signal has to go through, type if walls, etc. Also, you have a better chance with 2.4Ghz signal vs. A 5Ghz signal. But chances are a router alone will not give you a long enough range for that long of distance.
Why buy consumer junk? There is exceptional equipment out there that blows away anything you will ever buy in a store. I use equipment from Ubiquiti Networks® that never fails, and is never disappointing.
You want to go 400' and that sounds like across the yard. I have a ranch here that is about 4 miles wide by 16 miles long in the mountains outside San Jose and about a third of it is covered by WiFi. All equipment here is made by Ubiquiti. My longest hop is over 6 miles using my older NanoBridge M5 units and they work perfectly. (NanoBridge M5 units actually will make a perfect connection to about 26 miles with one at each end).
For you, I suggest Ubiquity LiteBeam M5 (if you are able to use 5Ghz). They are NOT expensive.
They have a MSRP of $49.00 and have a range of a few miles.
HERE is a link to the Ubiquiti Networks web page concerning this model.
If your target receiver is at a fixed location, you will only need one to do the job. If it is several locations in a building, you can add Access Points to distribute the signal around if needed. The receivers in these units are very sensitive. They can pick up a home WiFi router a few miles away even though that router is in someone's house.
You can purchase these on eBay but sellers there are over-charging everyone. The Ubiquity website has a link to resellers that will treat you right.
HERE is a link to the Ubiquity store. The LiteBeam M5 is in the first row of products shown.
Or.. you can go to WalMart or BestBuy and roll the dice buying what they sell.