Application 309 questions

Dear Friends,
I have some queries regarding my case application for my PR status and partner visa. I got my first PR in 2013 under 189, since then i have made one entry to Australia for visit only. From that time onwards I am doing job outside Australia till today. Now my PR will expire in Oct 2018 but i plan to extend it. Also i am married now with one baby.

1) will they extend my PR visa if i move there in Jan, 2018 till Oct, 2018? what is current extension rates and procedure?
2) can i apply extension from here?
2) if i apply for partner visa, will they grant it keeping in view short time in my case being sponsor?
3) should i include my baby (1 year) in my partner 309 application or a complete separate case will be filled for her?
4) if i include baby in partner application, will they charge separate fees for her?
5) if i file 309 application now, can i also file a new application for visit visa if she travels with me? will it not cancel the existing application for 309?