magenta max speeds overseas

I am living in Spain for 9 months. Have the Magenta Max plan, first few weeks I had really high speeds for data, now it’s down to super slow. I know they said it’s 5GB high speed for free then down to 256kbps, but it’s suuuuper slow. Two questions. 
 

1. Will I  receive a new 5GB of high speed in a new billing cycle? Or is it 256kbps for the rest of the way. 
    
2. Does anyone have experience buying a SIM card overseas for a long time? I am considering it but don’t want to be paying for a Spanish SIM card and Magenta Max at the same time. 
    
    

Thanks for the help.