Coauthoring a paper and presenting a poster is a lot more then a lot of students who do research will ever accomplish in ugrad. So yeah its no Goldwater scholar or Rhodes Scholar but it is significant. Your ECs sound good.
With a 35+ if you apply reasonably to a broad base of schools, a few reach schools, your state schools, and other schools that take a lot of out of state students and people with a broad range of stats, you will most likely get a good chance of getting in somewhere.
If you don't then SMP programs will be your best option, esp. going to a program that is more well known like BU MAMS, Drexel IMS, or the founding and best known of its type the Gtown SMP but chances are you might not need it. So do make an appt with admissions directors of your state schools and a few others of schools of interest.