The use of solvent depends on the nature of compounds expected to be excited in the extract and its polarity. Aqueous extract containing the polar compounds, so you need to use a polar solvent e.g. methanol, ethanol. However for TLC analysis you need to check the the solubility of your target compounds in the chosen solvent.
I agree with Erkan halay first you should try to solubilise whole constituent that may be possible in mixture of solvent like ethanol-water, methanol-water, or acetone- water. Water should be in minimum amount.
I think you should try with methanol with little portion of water, how much water?. Using the minimum necessary to dissolve all the extract , it means you should use methanol and add water drop by drop until the extract is dissolved. Of course you should try to use only some milligrams of your dry extract .