Hi Candyman
You have a property worth €200k and you have net borrowings of €200k
If you buy another property, you will have property worth €650k and borrowings of €650k. You shouldn't have such an exposure to property and interest rates. But in any event, the lender won't give you the money anway.
if your current home is not suitable for your needs, then you should sell it. It is better to remain in it while trying to sell it, as it is awkward to sell a house with a tenant in it.
When you have sold it, you will probably not have the deposit to buy a new house, so you can rent until you have accumulated the deposit.
If you have a tracker mortgage, ask the lender to do a deal with you. They may knock something off the mortgage in return for releasing them from their loss making loan.
Brendan