Interested in Neuroscience programs but lack research experience & grades
The only way to prove to your future advisor that you are capable of doing research is by doing research. Apply to be an RA (Research Assistant) in a neuroscience lab. This will give you enough experience and, importantly, will equip you with the general knowledge of the field. Being exposed to ongoing work will also allow you to start formulating your own research questions, which is an important skill that you'll definitely need in grad school. 

Now, how to increase your chances of getting a good RA position? 

(1) By applying early and demonstrating that you're serious about the job.

(2) By learning programming (as you mentioned). Technical skills are in very high demand! 

Many people end up in grad school after working as RAs for 2+ years, so there is no rush. Take your time and make sure that graduate school is really what you want. Good luck :)