Help uninstalling time capsule and going back to just Comcast/Xfinity modem

Hi, I'm a newbie and that that tech savvy. I would appreciate it if the forum could help me with the following.

Hardware: Macbook Air Mid 2012 running Mavericks
Time Capsule: A1355
Printer: Brother 2270dw setup to print wirelessly
Ipad 3 running os7
Iphone 5s running os7
Comcast/Xfinity gateway modem: Model DPC3939

My time capsule failed to back up for 10 days. Its been running like a champ ever since the day I bought it. I don't have the technical know how to fix it. I pulled up airport utility and it shows green on internet and but a blinking yellow on the time capsule itself. I clicked on time capsule and chose "bridge mode" and that got it to green. I ran time machine and left it overnight only to find out it failed to back up. I decided its time to retire the A1355. I ordered the G-Technology 3TB G-DRIVE with Thunderbolt External Hard Drive from Apple and it should arrive next next week.

When I disconnected the time capsule from my Xfinity modem I lost my internet connection but re-gained it when I plugged it back in. How is this possible if both my time capsule and modem is capable of producing a my wifi signal?

I called Comcast and they said they'll have to call for a technician and there will be a fee but I have to wait a week for service. Is this a simple fix? If so, How do I get my internet connection to come solely from my Xfinity modem?

Will this effect my wireless printer?

Is it necessary to partition the 3tb hard drive? (I just need it to back up, nothing fancy)

Is it easy to set up time machine on the 3tb hard drive?

Kind regards

One thing at a time. Let's get the wireless working again. The reason you lost your wireless signal is because your TC was providing it from the Comcast LAN input. Your modem according to the specs is a combination router - modem. What you need to do is access the internal menu of the unit and turn the wireless signal on. Do you have a booklet that came with your modem? If not, get on the net and download a manual for it and then follow the instructions as given in the manual. It should be easy to setup and get running in short order. Let us know.

Hi Chscag! Thank you for your response. sorry it took so long. 24hours after I made that posting my boss told me I would be on a business trip overseas. I just got home and I was able to access my comcast modem internal menu and voila! It worked =)