Vistaprint is a great company to work for for everyone but the culture is especially supportive for women. My two pieces of advice:
1) Don't apologize for having responsibilities outside of work. Get your work done, be flexible (sometimes work at night or a few hours on a weekend to get your work done) but don't apologize when you have to leave at 5 to pick up your kid.
2) Don't over explain! "I need to leave because my kids are xyz...." Just do it, your work will show for your dedication and you will be recognized for it.
Best of luck!