Virtual Assistant Needed with PERFECT English

I need a VA, but have not been able to wrap my head around the best way to use a VA. So, the candidate that I hire will have to be driven and be able to find solutions. You English must be perfect, as this job will require some phone calling.

Some details:
1. I run two businesses at this time. A non-profit and a marketing company. I need help with both of them. 2. Knowledge of web design and graphic design is helpful but not a must.
3. I plan to start by including the VA on all emails. I will expect the VA to read the emails, familiarize themselves with the businesses. I will expect the VA to make suggestions as to where you can be helpful.
4. I see the VA as being the project manager for our design projects. Keeping tabs on the staff, and communicating with me, and in some cases the client, the progress of projects.
5. The VA will help with donor management for the non-profit, tracking donations, preparing thank you notes, etc.

To be considered as a candidate, please respond with suggested solutions for these issues:
1. Phone calls: How do you suggest doing this? I would need you to have an American line for people to call, and an American number to show up in people's caller ID. Please suggest some services that we could use.
2. Sending Letters: I would need you to prepare thank you letters to be sent to donors. We need a service where you can prepare the letters, send them in and then they are printed and sent to me to be signed and mailed. Please suggest some services that we could use.

Besides your suggestions to the above, please send your resume and references.