How to enable wireless WIFI in Wateen Outdoor CPE 450

I am using Wateen outdoor CPE 450 it connects to my desktop PC through Ethernet cable, now i wanted to use same connection on laptop which have a WIFI option in it but the wateen outdoor unit does not supports WIFI unless it is connected through Wireless router. I read some information here on this website related to WIFI router but still there are some question which i like to answer and hope it could be answered by some knowledgeable members.

1. Is it true that in Wireless WIFI speed tends to fluctuate constantly?. If it is true than how much speed i will get even in worse condition. I have to use it in my house and its covered area is 160 sq. yards. I am getting 4 signals most of the time out of 5 on my CPE.

2. I gather information about routers and least priced one is about Rs.1750 of TPLink TL-WR740N '150Mbps Wireless N Router'. Is it okay considering my covered area and signal strength.

3. Is it easy to install and operate both connections specially when person not know much of networking?.

4. Can i also use Wateen blade device as a WIFI router only.?

5. if possible please suggest any other alternate than a wireless router?

I really appreciate if someone shed some knowledge on the questions i ask.

Thanks

where do you live and when you got outdoor device, just asking becoz i am on hold.