Hm, if even resets don't work anymore, it sounds like hardware failure. Router can get really warm (depends on traffic and built in WLAN card) but hot sounds like something's broken.
Linksys had great routers (btw it is/was possible to run Linux firmware on them, so you were able to give more power on the antenna outputs ) but after the WRT54xx series, quality wasn't the same.
The idea with better antennas from Brasil will help to increase the level at devices, but it seems it worked before so why not now with the original antenna(s)?
I would recommend buying a new one. The price for a good router isn't that high and they have nice features like USB ports for printers, harddiscs, .....
If I were near you, I would try to measure and fix it, but... yeah
Another problem worldwide came up the last years. 2,4GHz router were installed everywhere and so it's sometimes really hard ro find a free channel. Today it works much better to have a router with 2,4GHZ and 5GHz WLAN. If the device (laptop etc.) has a suitable card for it, it will take 2,4 or 5GHz.
New one could help to have better level in some areas of the house too.
Some I played with a while ago were TP-Link routers -> http://www.tp-link.u...nd N600 or N750
Easy to config and good to work with so far (also heard that from others). Netgear (never liked Netgear years ago) brought some nice Dualband router (with built-in antennas) with Linux firmware already installed.