Hi Blondie88,
It is a very simple process and there is a ton of information available out there to help. I am actually English but live in Germany and hence can understand your situation. However, I can confirm that all major garages will be able to help you install new rims/tyres. I actually did this at Vergoelst just the other day and have previously used ATU as well - not sure if you have them in Austria.
I have bought 2 sets of rims from Ebay and been very happy with the price and quality of the purchases. I then bought the tyres from the the garages and got them to fit them. I will often do this for getting a Winter & Summer set for a new car.
What you need to be careful of making sure that you get rims that will fit. As an example here
www.wheel-size.com
you can find the Rim width and bolt pattern that you need - you can then use these in Ebay to filter the offers.
As with everything in life make sure to check 2 or 3 times that you have a valid configuration before buying. I would also advise trying to buy locally as you might want to check for curb rash or other damage.
Have fun
Dave
It is a very simple process and there is a ton of information available out there to help. I am actually English but live in Germany and hence can understand your situation. However, I can confirm that all major garages will be able to help you install new rims/tyres. I actually did this at Vergoelst just the other day and have previously used ATU as well - not sure if you have them in Austria.
I have bought 2 sets of rims from Ebay and been very happy with the price and quality of the purchases. I then bought the tyres from the the garages and got them to fit them. I will often do this for getting a Winter & Summer set for a new car.
What you need to be careful of making sure that you get rims that will fit. As an example here

MINI Cooper 2015 - Wheel & Tire Sizes, PCD, Offset and Rims specs
MINI Cooper 2015 - Find out the correct alloy wheel fitment, PCD, offset and such specs as bolt pattern, thread size(THD), center bore(CB) for MINI Cooper 2015
you can find the Rim width and bolt pattern that you need - you can then use these in Ebay to filter the offers.
As with everything in life make sure to check 2 or 3 times that you have a valid configuration before buying. I would also advise trying to buy locally as you might want to check for curb rash or other damage.
Have fun
Dave