im going to link you to my reply to a different post related to jhu ei: http://talk.collegeconfidential.com/summer-programs/1905904-cty-or-jhu-engineering-innovation.html
sorry i have no idea what the toefl is D:
what you wrote in your application looks good so far. in addition to expressing your interest in the curriculum and in networking with other students, you should also state your past experiences with engineering or other stem subjects. really show your passion and enthusiasm when you write your application.
attending a summer program in school x will help you get into any school. being productive over the summer is looked at positively. if you attend jhu ei, your attendance will likely improve your college application to jhu.
let me know if you have any questions or if you need further clarifications on anything 