Had similar issue...if you are not at full bars your speed is already cut in half. Also, I'll agree with Grenville that you should get a new router, but disagree with the chose of the rosewill g, which will cut your speed significantly from the n you have. Is your cisco a regular home router or is it a business grade one? I researched this at length and routers are like computers in that all are not equal...they have cpu's and memory that affect their speed. The Asus RT-N16 http://www.newegg.com/Product/Product.aspx?Item=N82E16833320038
is the screamer of routers...significantly more powerful cpu than other routers allows faster thruput and better handling of the multiple data streams your office probably uses. You'll want to flast to the latest firmware as older versions are difficult. I had speed problems using the comcast modem that came wwith my business account that resolved after switching.
Regarding ddwrt, it is an open source firmware for routers. Just as a computer will run differently with different os's, so to with different firmware on routers. ddwrt only runs on compatible routers and applying it will be a whole education in itself. If you try to flash it to an incompatible router you can "brick", or ruin your router. As an added bonus, the asus router does support it and has a mechanism in place to restore the previous firmware in case you do mess up the upgrade (thus avoiding ruining the router). I have not tried ddwrt with my asus as it is humming along perfectly with the newest version of the asusu firmware.
In any case, for $80 i'd try the Asus, be sure your laptop is running with an N card and latest drivers, and position router centrally if necessary to get full signal strength (the Asus has three antenna's so may give you better coverage than your current router too.)I hope this helps.
Art Treiman