It looks to me like a problem specific to your laptop's wireless drivers, antenna, or underlying wireless chip used. It could also be a compatibility problem between the wireless chipset used on the router vs. the wireless chipset used on your laptop.
Tools like inSSIDer are not necessarily going to help determine what the actual issue is -- it can help determine if your signal level is crap compared to another identical device, but it's not helpful when it comes to things like Product A vs. Product B. What you'd actually need is a full 802.11 protocol and frequency spectrum analyser. These are very expensive and require great technical expertise.
Wireless is one of the worst, most unreliable things I have ever had the "joy" of dealing with both professionally and personally. It's just utter garbage; it blows my mind how the entire world uses something so unreliable. It's an awful, awful piece of technology. Just awful.
Anyway -- engage Toshiba and make this their problem. You can fiddle around with drivers and wireless settings (though keep in mind adjusting ANY wireless NIC settings on your laptop, or on the router, often causes the wireless chip to be completely reset -- this often results in things that work briefly then fail down the road, so a simple "i changed X setting and it fixed it" is not sufficient, you need to test over a long period of time (1-2 weeks, no joke)), but my advice would be not to do any of that and instead engage Toshiba from the get go. If the problem is easily reproducible, that should help them out greatly. All this is assuming the product is still under warranty; if it's not, good luck solving the issue.--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.