It sounds to me that your router is loosing its settings. In the memory of the router when you go to its I.P. address you can save the settings. But the connection will drop if the settings are "changed" or "forgotten".
I had this experience with my friends router, it kept dropping signals because the router could not retain the settings.
1.Go into your router ip address in your browser (Ethernet connected)
2.Go threw the steps of setting up the wireless.
If it keeps dropping it then I might contact the manufacturer for a new one (1 year warranty)
Is it a trend-net router?