I have some ideas that my help you out
Try and put the router as central in your house as you can, you might get by with only one router.
You could also look into getting higher db antennas,
or a higher powered router like the Asus N66, Asus N56, Netgear WNDR4500, ect. They will run you about $150-180-ish but have excellent range.
or you want to use your existing equipment and if your routers can support WRT firmware (DD-WRT, OpenWRT, Tomato, Gargoyle, ect - can add features to your $80 router that essentially turn it into a $300 router.). You can flash your secondary routers (or all of them if you want) and configure them as repeaters, bridges, ect. for whatever your needs are.
As an example - My laser printer is hooked up through ethernet to a router bridged wirelessly to my main network.