Please have a look at the following parameters in your network:
Routers (the exception proves the rule)
a. WLAN N: 300MBit/s or 450MBit/s Even with a full signal the netto rate will not go higher that 200MBit/s which means a possible transfer maximum of about 25MB/s. But in reality you will experience about half of this speed 10 to 14MB/s.
b. WLAN G: 54MBit/s The maximum would be about 6.75MB/s, in reality about 3 to 4 MB/s max speed. In bad receiving conditions it could be much worse, e.g. about 1.5MB/s
Many router do have a 100MBit switch build-in. You will experience transfers about 10 MB/s. Routers with GBit-switch build-in should be capable of giving you maximum speed possible. But be aware that many so called GBit-routers are not able to provide IP/IP transfers at high speeds. A lot of router are limited to about 200 or 400MBit/s. If you are in doubt please try to get your hands on good reviews of your router.