Hi and welcome to Just Answer!
Different expert here - please allow me to assist.
Your original question was - How much tax would i pay on this amount ($4500.00)
Because you are living and working in a foreign country - you are likely eligible for a foreign earned income exclusion - and pay no US income taxes
However - distribution from the 401k is not earned income for that purposes and may not be excluded. It will be taxable at your marginal tax rate - which is determined without considering a foreign earned income exclusion.
For instance - if your total income - before the foreign earned income exclusion - is $70,000 (converted into US currency) - and you are likely in 25% federal tax
bracket - the distribution from the 401k will be taxed at 25% tax rate.
Please take a look at tax rate schedule on the last page in this publication - www.irs.gov/pub/irs-pdf/i1040tt.pdf
Your second question - And do i have to wait until I'm 70 1/2 to withdraw the money?
No need to wait.
There is no penalty for distribution from the inherited 401k - and you may take the full distribution immediately. That is one option.
Inherited 401k account may not be treated as your own and may not be rolled into your own IRA - but may be rolled over to specially titled "inherited IRA" - that would be another option if you want to delay or spread distributions over several years.
If your father was above 70 1/2 and already started required minimum distribution (RMD) - you must continue such distributions.
Let me know if you need any help.