Reddit mentions of Buffalo AirStation HighPower N300 Open Source DD-WRT Wireless Router (WHR-300HP)

http://www.amazon.com/BUFFALO-AirStation-HighPower-Wireless-WHR-300HP/dp/B0096239EC/ref=sr_1_2?s=electronics&ie=UTF8&qid=1372706187&sr=1-2&keywords=buffalo

That seems to be in your price range and has the ability to flash DD-WRT on it to manually increase radio strength.

Exactly. I'd greatly recommend that the "boxes" connected "by radio" are 5GHz like these. These won't double as hotspot so you should get either a router to have a separate network (I'd recommend a buffalo as they come with DD-WRT preinstalled or easily installable) or a DIR-615 which keep revising hardware and usually takes a while to have a compatible DD-WRT. If you don't want any hotspot-specific features you can get a simple AP or any router.

I just bought my first DD-WRT router the other day for about $40. Haven't gotten around to setting up the VPN but it has much more in terms of options compared to my last router. Looks better too

Check out Buffalo's stuff. I've had pretty good luck with the [WHR-300HP] (http://www.amazon.com/BUFFALO-AirStation-HighPower-Wireless-WHR-300HP/dp/B0096239EC/ref=sr_1_2?ie=UTF8&qid=1377196156&sr=8-2&keywords=buffalo+router). I also have a [WHR-HP-G54] (http://www.newegg.com/Product/Product.aspx?Item=N82E16833162134) that is discontinued, but still running strong. Maybe that quality translates to the [WCR-GN] (http://www.amazon.com/BUFFALO-AirStation-N150-Wireless-Router/dp/B003ZM17R0/ref=sr_1_5?ie=UTF8&qid=1377196156&sr=8-5&keywords=buffalo+router), which seems to be the replacement.

Edit - Forgot to mention that DD-WRT and buffalo generally play nice.