Using antenna on Sim800 module

Hii… Im using a maker and hacker sim800 module…

While working with the module, the antenna as seen here, was detached unfortunately. I tried to solder the antenna back, but now im unable to make calls or receive sms on the module. So, could you please suggest me a better alternative for the antenna. Please tell me what all connectors and components to buy for the same. Secondly in my project, the antenna needs to be put outside the enclosure, while the module would stay inside a housing. Please guide me here.

You can just put a 4cm wire if you are experimenting with the board. it will work.