Modes of transport

Dare I say I've started to think about what is actually going to happen when this teeny tiny human finally arrives into the world and what I might need to get sorted. Granted, I have ALOT of stuff already from when Liv was young, and we dont know the sex yet so we might still be able to use Liv's old clothes, but there are a few things that are playing on my mind and one of them is my mode of transport.

And I'm not talking cars. Pushchairs/prams etc etc. I am caught in a haze of what decision do I make. Currently, I have a REALLY old Quinny buzz that Liv adores and so do I but it is quite old (we brought it second hand) and to be perfectly honest I still shove Liv in there when I am out and about doing tasks (shopping etc) because lets face it NO-ONE appreciates a toddler who either walks at approx one step per hour whilst trying to pick up dried up chewing gum, or one that races around your feet at the speed of light, often tripping you up, and so, my thoughts of still using a pushchair with Liv remains., HOWEVER, Liv will turn two approx 3 weeks before the new baby is due and therefore THIS is where my conundrum begins...so my options are buying a double buggy (I dont know the first thing about buying a double buggy btw, all I know is that they are BIG) or dont buy one but buy a buggy board for my current one for Liv to hop onto if she is being a lazy ass, OR buy a baby carrier for the newborn so Liv can still have the Quinny. But herein lies the many issues that I am currently facing:

• What happens if Liv hits two and decides HELL NO is she being strapped down and therefore If I buy a double buggy wont get any use?
• What happens if I DON'T buy a double buggy and expect Liv to use a buggy board but what if the child is knackered and wants to sleep somewhere? 
• If I buy a baby carrier, and the baby is born in August and its HOT, will the baby even be able to go into it ON me - wont it be too hot?
• I am on the tightest budget ever

I just don't know what to do? I love the idea of a double buggy (obviously with an attachment for the newborn to have a carrycot to sleep) but what ones are available on the market at a reasonable price. I've been told continuously that Bugaboo Donkey's are AMAZING but I'm not gonna lie to you all, I cant afford a spare wheel off a bugaboo let alone buy one for real. How easy are these double's to fold up? and am I going to need a PHD to work out how to get out up? 

The idea of a buggy board also sounds appealing but then Liv gets mega scared at the roundabout at the park, so surely she's NOT gonna like standing on the board (plus she has a habit of sporadically jumping off the roundabout with no warning - thats gonna be hella messy on a buggy board, I dont fancy walking over my own child) 

Again with the baby carrier, I used a Baby Bjorn with Liv and yeah the thing pretty much broke my back but it was dead handy to have hands free, and with a toddler I'm thinking this is going to be key!?!? but will it be plausible to use this ALL the time with baby and therefore not need a pushchair/carrycot?

It truly is some sort of 4-wheeled rollercoaster and I truly don't know what to do for the best - SO I need your help. Any advice, opinions, brands to looks out for or to turn too, anyone wanna give me the winning lottery numbers so money is no object (just kidding... .NOT) Please help, my brain is frazzled!