Dropped wifi signal

I own a 700 Mhz original eMac with 768 MB of RAM running on Tiger 10.4.10. I live at an apartment complex that provides wireless internet connection to its tenants. I've moved to another unit in the same complex and now, instead of having the internet antenna only 20 feet from my computer, it is now about 40 YARDS from my eMac. Other than experiencing slow download speeds, I had no problem connecting to the internet in my old apartment. Since moving into my new unit, I've had a problem with my eMac connecting to the internet, usually dropping the complex's wifi signal without warning within 30 minutes. My machine is unable to reconnect to the internet after restarting and it sometimes reconnects after I put my eMac to sleep for a couple of hours. Further, not only does my eMac drop the wifi signal, it seems to stop scanning for other available networks to join. Obviously, since I live in an apartment complex, I should be able to pick up other tenants' wifi signal (some tenants have opted to have their own DSL account) who live close to me. In my old unit, my eMac easily picked up my neighbors' signal, but in my new unit, my eMac initially picks up wifi signals around me including the one provided by my apartment complex, then drops the wifi signal after about 5-10 minutes. Even while using the Internet Connect software, my eMac is apparently not picking up any wifi signal from anywhere. Would it help to boost the complex's wifi signal by purchasing an external antenna? If so, where on my eMac would I connect the antenna? If I need to boost the complex's signal, would an Airport Express do the job? If not, can anyone recommend another wifi range extender (if one exists)? If an external antenna is not the solution, does anyone have any other suggestions to solve my problem? Incidentally, I recently had Elgato's EyeTV200 installed and I'm wondering if it is part of my signal dropping problem. Has anyone had problems connecting wirelessly after installing the software for the EyeTV200? Is there is a problem with my Airport card? Any other suggestions? Thanks to all who answer!

Addendum (9/26/07) - As a test, I pulled out a wireless modem that I inherited from a former roommate and fired it up to see if my eMac would pick up it's signal. (I'm not a true geek - more of a geek wannabe - and I find it interesting that this modem still sends out a wireless signal even though there is no active DSL account or an active phone line. Maybe that's the way all wireless ADSL modems work, but, I don't know. Like I said, I'm not a true geek.) The modem sent out a signal, and my eMac picked it up - at least, for a while. After about ten minutes, my eMac dropped all of the surrounding wifi signals and about five minutes after that, it dropped the signal from my modem. I've heard via the discussions page on www.apple.com/support that there have been some cases of users experiencing dropped wifi signals after upgrading to Tiger and I'm wondering if any of you out there experience the same thing I am. It is obvious to me that if I want to connect to the internet, I going to either a) get my own DSL account and connect the modem to my computer via an ethernet cable or b) find some sort of a bridge between the complex's wireless signal and my computer. If I go for the latter, can the Airport Express function as that bridge? I'm hoping that I could plug the Express into the wall, have it pickup the complex's wifi signal and send it to my eMac via an ethernet cable. Will this work?