Urgent Question regarding visa

[gkds52]

Dear friends
This is my first time in this forum, i've been reading and searching but I'm very confused.I feel bad because I couldnt do my homework good enough and thats why i m writing here....
This is my situation:
I'm a turkish national, currently living in the USA with a green card, and working in the USA as a manager for a US company , that has an UK office too. I need to go on a Business trip to our london office for 2 weeks. Then I'll have frequent visits thruout the year for a week or two weeks in every 3-4 months.
What type of visa should I apply ? Is it me who will apply or is it my company that needs to Apply?
Please help me as I need to figure this asap.
Thank you in advance to all.

[Lucapooka]

What activity will you be doing at the UK-based subsidiary?

[gkds52]

What activity will you be doing at the UK-based subsidiary?

I work here as the director of the support services and i have 4 people in our london office working for my team. I ll need to touch bases with them.