How to set a lookup field by name

Hi, I am using PHP SDK in CRM, and I created a custom lookup field referring to the Accounts. The only way to search that field value is by (unique) name, and it should return an account.

I tried something like

$record1->addKeyValue('my_new_account_lookup_field', 'My Account Name to Search')

But the error I get is

400 error INVALID_DATA my_new_account_lookup_field

Probably because I set a string, instead of the account resource? But how do I search the account record(s) by Name?

Additionally, is there a way to set additional parameter during search, like Account Type, and not just the Account Name?