Why would you put ATP if you don't have an ATPL?
You can 'convert' anything - PPL, CPL or ATPL to FAA as long as you meet the necessary requirements, take the written and flight tests. But if you want to get an FAA certificate without passing a flight test, you need a 61.75 certificate which is essentially a validation of your foreign licence. Also known as a piggyback or OTBO. Whatever level of licence you have, since 1997 they'll only issue you a PPL.
The good news is that you're working in the US, so presumably you have a green card or citizenship? In that case I'd recommend getting all your FAA certificate and maybe building time as flight instructor.