Insert Data Into Tables Linked by Foreign Key

Customer
==================
Customer_ID | Name

Order
==============================
Order_ID | Customer_ID | Price

To insert an order, here is what I need to do usually,

For example, "John" place "1.34" priced order.

(1) Get Customer_ID from Customer table, where name is "John"
(2) If there are no Customer_ID returned (There is no John), insert "John"
(3) Get Customer_ID from Customer table, where name is "John"
(4) Insert "Customer_ID" and "1.34" into Order table.

There are 4 SQL communication with database involved for this simple operation!!!

Is there any better way, which can be achievable using 1 SQL statement?

Thanks and Regards
Yan Cheng CHEOK