Help picking my next lens

[SMN-Sony]

I'm using a Sony A100 with the Sony 75-300 4.5-5.6. I'm looking to apgrade to something like:

- New Sony 70-200 f/2.8 for around $2000 damn thats allot of money!
- Used Minolta 200mm f/2.8 APO for around $900. Heard this is a great lens but does not always work great with the Sony camera's.

or should I look at the Sigma or Tamron alternative's?

This would mainly be used to sports picture's ... soccer & track/cross country.

All suggestions and comments will be appreciated.

[SONYNUT]

the sigma 70-200 2.8 apo works fine for me.. i picked it up for 350 on ebay

[DonSchap]

I took this with my Tokina ATX-840 (Model I) AF 80-400mm f/4.5-5.6, which can really dig in and focus sharply. If you can get one ... I got mine for $300 from Japan.

EXIF: 180mm - f/8 - 1/60 - ISO-400 - Pop-up flash - M - single shot

Here's a crop ...